1
|
Zhou Y, Leahy K, Grose A, Lykins J, Siddiqui M, Leong N, Goodall P, Withers S, Ashi K, Schrantz S, Tesic V, Abeleda AP, Beavis K, Clouser F, Ismail M, Christmas M, Piarroux R, Limonne D, Chapey E, Abraham S, Baird I, Thibodeau J, Boyer KM, Torres E, Conrey S, Wang K, Staat MA, Back N, L’Ollivier C, Mahinc C, Flori P, Gomez-Marin J, Peyron F, Houzé S, Wallon M, McLeod R. Novel paradigm enables accurate monthly gestational screening to prevent congenital toxoplasmosis and more. PLoS Negl Trop Dis 2024; 18:e0011335. [PMID: 38805559 PMCID: PMC11132520 DOI: 10.1371/journal.pntd.0011335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 04/01/2024] [Indexed: 05/30/2024] Open
Abstract
BACKGROUND Congenital toxoplasmosis is a treatable, preventable disease, but untreated causes death, prematurity, loss of sight, cognition and motor function, and substantial costs worldwide. OBJECTIVES We asked whether high performance of an Immunochromatographic-test (ICT) could enable accurate, rapid diagnosis/treatment, establishing new, improved care-paradigms at point-of-care and clinical laboratory. METHODS Data were obtained in 12 studies/analyses addressing: 1-feasibility/efficacy; 2-false-positives; 3-acceptability; 4-pink/black-line/all studies; 5-time/cost; 6-Quick-Information/Limit-of-detection; 7, 8-acute;-chronic; 9-epidemiology; 10-ADBio; 11,12-Commentary/Cases/Chronology. FINDINGS ICT was compared with gold-standard or predicate-tests. Overall, ICT performance for 1093 blood/4967 sera was 99.2%/97.5% sensitive and 99.0%/99.7% specific. However, in clinical trial, FDA-cleared-predicate tests initially caused practical, costly problems due to false-positive-IgM results. For 58 persons, 3/43 seronegative and 2/15 chronically infected persons had false positive IgM predicate tests. This caused substantial anxiety, concerns, and required costly, delayed confirmation in reference centers. Absence of false positive ICT results contributes to solutions: Lyon and Paris France and USA Reference laboratories frequently receive sera with erroneously positive local laboratory IgM results impeding patient care. Therefore, thirty-two such sera referred to Lyon's Reference laboratory were ICT-tested. We collated these with other earlier/ongoing results: 132 of 137 USA or French persons had false-positive local laboratory IgM results identified correctly as negative by ICT. Five false positive ICT results in Tunisia and Marseille, France, emphasize need to confirm positive ICT results with Sabin-Feldman-Dye-test or western blot. Separate studies demonstrated high performance in detecting acute infections, meeting FDA, CLIA, WHO REASSURED, CEMark criteria and patient and physician satisfaction with monthly-gestational-ICT-screening. CONCLUSIONS/SIGNIFICANCE This novel paradigm using ICT identifies likely false positives or raises suspicion that a result is truly positive, rapidly needing prompt follow up and treatment. Thus, ICT enables well-accepted gestational screening programs that facilitate rapid treatment saving lives, sight, cognition and motor function. This reduces anxiety, delays, work, and cost at point-of-care and clinical laboratories. TRIAL REGISTRATION NCT04474132, https://clinicaltrials.gov/study/NCT04474132 ClinicalTrials.gov.
Collapse
Affiliation(s)
- Ying Zhou
- Departments of Ophthalmology and Visual Science, The University of Chicago, Chicago, Illinois, United States of America
| | - Karen Leahy
- Department of Obstetrics and Gynecology, The University of Chicago, Chicago, Illinois, United States of America
| | - Andrew Grose
- Departments of Ophthalmology and Visual Science, The University of Chicago, Chicago, Illinois, United States of America
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
| | - Joseph Lykins
- Departments of Ophthalmology and Visual Science, The University of Chicago, Chicago, Illinois, United States of America
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
| | - Maryam Siddiqui
- Department of Obstetrics and Gynecology, The University of Chicago, Chicago, Illinois, United States of America
| | - Nicole Leong
- Department of Obstetrics and Gynecology, The University of Chicago, Chicago, Illinois, United States of America
| | - Perpetua Goodall
- Department of Obstetrics and Gynecology, The University of Chicago, Chicago, Illinois, United States of America
| | - Shawn Withers
- Departments of Ophthalmology and Visual Science, The University of Chicago, Chicago, Illinois, United States of America
| | - Kevin Ashi
- Departments of Ophthalmology and Visual Science, The University of Chicago, Chicago, Illinois, United States of America
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
| | - Stephen Schrantz
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
- Chicago Medicine, The University of Chicago, Chicago, Illinois, United States of America
- Department of Pediatrics, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
- Department of Medicine, The University of Chicago, Chicago, Illinois, United States of America
| | - Vera Tesic
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
- Chicago Medicine, The University of Chicago, Chicago, Illinois, United States of America
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
| | - Ana Precy Abeleda
- Chicago Medicine, The University of Chicago, Chicago, Illinois, United States of America
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
| | - Kathleen Beavis
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
- Chicago Medicine, The University of Chicago, Chicago, Illinois, United States of America
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
| | - Fatima Clouser
- Departments of Ophthalmology and Visual Science, The University of Chicago, Chicago, Illinois, United States of America
| | - Mahmoud Ismail
- Department of Obstetrics and Gynecology, The University of Chicago, Chicago, Illinois, United States of America
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
- Chicago Medicine, The University of Chicago, Chicago, Illinois, United States of America
| | - Monica Christmas
- Department of Obstetrics and Gynecology, The University of Chicago, Chicago, Illinois, United States of America
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
- Chicago Medicine, The University of Chicago, Chicago, Illinois, United States of America
| | | | | | - Emmanuelle Chapey
- Institut des agents infectieux, Hôpital de la Croix-Rousse, Lyon, France
| | - Sylvie Abraham
- Laboratory of Parasitologie, Bichat-Claude Bernard Hôpital, Paris, France
| | - Isabelle Baird
- The College, The University of Chicago, Chicago, Illinois, United States of America
- Global Health Center, The University of Chicago, Chicago, Illinois, United States of America
| | - Juliette Thibodeau
- The College, The University of Chicago, Chicago, Illinois, United States of America
- Global Health Center, The University of Chicago, Chicago, Illinois, United States of America
| | - Kenneth M. Boyer
- Department of Pediatrics, Division of Infectious Diseases, Rush Presbyterian Hospital and Medical Center, Chicago, Illinois, United States of America
| | - Elizabeth Torres
- Group of Molecular Parasitology (GEPAMOL), Center of Biomedical Research, Faculty of Health Sciences, University of Quindio, Armenia (Quindio), Colombia
| | - Shannon Conrey
- University of Cincinnati and Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Kanix Wang
- Carl H. Lindner College of Business, The University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Mary Allen Staat
- University of Cincinnati and Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Nancy Back
- University of Cincinnati and Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Coralie L’Ollivier
- Centre National de Référence Toxoplasmose—Pôle Sérologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
- IHU-Méditerranée Infection, Assistance Publique Hôpitaux de Marseille (AP-HM), Marseille, France; Aix Marseille University, IRD, AP-HM, SSA, VITROME, IHU Méditerranée, Marseille, France
| | - Caroline Mahinc
- Parasitology and Mycology Laboratory, Pôle de Biologie-Pathologie, University Hospital of Saint Etienne, Saint Etienne, France
| | - Pierre Flori
- Parasitology and Mycology Laboratory, Pôle de Biologie-Pathologie, University Hospital of Saint Etienne, Saint Etienne, France
| | - Jorge Gomez-Marin
- Group of Molecular Parasitology (GEPAMOL), Center of Biomedical Research, Faculty of Health Sciences, University of Quindio, Armenia (Quindio), Colombia
| | - Francois Peyron
- Institut des agents infectieux, Hôpital de la Croix-Rousse, Lyon, France
| | - Sandrine Houzé
- Laboratory of Parasitologie, Bichat-Claude Bernard Hôpital, Paris, France
| | - Martine Wallon
- Institut des agents infectieux, Hôpital de la Croix-Rousse, Lyon, France
| | - Rima McLeod
- Departments of Ophthalmology and Visual Science, The University of Chicago, Chicago, Illinois, United States of America
- Pritzker School of Medicine, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
- Department of Pediatrics, Division of Infectious Diseases, The University of Chicago, Chicago, Illinois, United States of America
- Department of Medicine, The University of Chicago, Chicago, Illinois, United States of America
- The College, The University of Chicago, Chicago, Illinois, United States of America
- Global Health Center, The University of Chicago, Chicago, Illinois, United States of America
| |
Collapse
|
2
|
Voyiatzaki C, Zare Chormizi AD, Tsoumani ME, Efstathiou A, Konstantinidis K, Chaniotis D, Chrysos G, Argyraki A, Papastamopoulos V, Kotsianopoulou M. Seroprevalence of Toxoplasma gondii among HIV Positive Patients under Surveillance in Greek Infectious Disease Units: A Screening Study with Comparative Evaluation of Serological Methods. Pathogens 2024; 13:375. [PMID: 38787227 PMCID: PMC11123859 DOI: 10.3390/pathogens13050375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/25/2024] Open
Abstract
This study aims to screen for IgG antibodies against Toxoplasma gondii (T. gondii) in the sera of 155 newly diagnosed Human Immunodeficiency Virus (HIV) positive patients under surveillance in Greek Infectious Disease Units. Additionally, risk factors based on patient demographics were examined, and a comparative evaluation of commercially available serological methods was conducted. Three methods were employed to detect IgG antibodies against T. gondii: Enzyme-Linked Immunosorbent Assay (ELISA), Indirect Immunofluorescence Antibody Test (IFAT), and Western Blot (WB), which was used as a reference here. Forty-nine sera samples were true-positive for IgG antibodies against T. gondii, resulting in a 31.61% positivity rate, and the immunoassay test statistical reliability analysis resulted in higher IFAT accuracy (90.97%) compared to ELISA (76.26%). Furthermore, statistical analysis of demographic and immunological data included in the study placed female and foreign/non-Greek individuals at 2.24 (p = 0.0009) and 2.34 (p = 0.0006) times higher risk of positive T. gondii IgG testing compared to their male and Greek counterparts, respectively. Our findings on positivity rates and comparative serology underscore the importance of early and suitable screening measures for newly diagnosed HIV+ patients to mitigate the life-threatening outcomes that may arise from a potential subsequent T. gondii activation.
Collapse
Affiliation(s)
- Chrysa Voyiatzaki
- Department of Biomedical Sciences, Division of Medical Laboratories Science, University of West Attica, 12243 Athens, Greece
| | - Apollon Dareios Zare Chormizi
- Department of Biomedical Sciences, Division of Medical Laboratories Science, University of West Attica, 12243 Athens, Greece
| | - Maria E. Tsoumani
- Department of Biomedical Sciences, Division of Medical Laboratories Science, University of West Attica, 12243 Athens, Greece
| | - Antonia Efstathiou
- Department of Biomedical Sciences, Division of Medical Laboratories Science, University of West Attica, 12243 Athens, Greece
- Immunology of Infection Group, Department of Microbiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Konstantinos Konstantinidis
- Department of Medicine, Laboratory of Biology, Democritus University of Thrace, Dragana, 68100 Alexandroupolis, Greece
| | - Dimitrios Chaniotis
- Department of Biomedical Sciences, Division of Medical Laboratories Science, University of West Attica, 12243 Athens, Greece
| | - Georgios Chrysos
- Second Department of Internal Medicine, Tzaneio General Hospital of Piraeus, 18536 Athens, Greece
| | - Aikaterini Argyraki
- Department of Internal Medicine, Sotiria Thoracic Diseases General Hospital, 11527 Athens, Greece
| | - Vasileios Papastamopoulos
- 5th Department of Internal Medicine, Infectious Diseases Unit, Evaggelismos General Hospital, 10676 Athens, Greece
| | - Marika Kotsianopoulou
- Department of Public Health Policy, School of Public Health, University of West Attica, 11521 Athens, Greece
| |
Collapse
|
3
|
Rahman SU, Akbar H, Shabbir MZ, Ullah U, Rashid MI. Newly optimized ELISA kit and LAT reveal significantly higher seroprevalence in sheep raised in agro-ecological zone as against range-ecological zone, with a significant association of meteorological parameters. PLoS One 2023; 18:e0290374. [PMID: 38051753 DOI: 10.1371/journal.pone.0290374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 08/07/2023] [Indexed: 12/07/2023] Open
Abstract
BACKGROUND Toxoplasma gondii is a zoonotic and foodborne intracellular parasite capable of inducing congenital infections, stillbirths and abortions in humans and animals, globally. The consumption of undercooked or raw mutton is "one of the vital risks" for acquiring toxoplasmosis: an asymptomatic condition in healthy persons, while life-threatening in immunodeficient individuals like "HIV/AIDS" patients. OBJECTIVES The current study has multiple objectives: to optimize a newly ELISA kit for Sheep, to find out the seroprevalence of ovine toxoplasmosis of two ecological zones of the Punjab, Pakistan through LAT and newly Optimized Sheep ELISA kit, to do the comparison of efficacies of various tests (LAT with newly Optimized ELISA kit and newly Optimized ELISA kit with commercial ELISA kit) and to determine the different meteorological parameters as the risk factors for T. gondii infection in sheep. METHODS A cross-sectional study was conducted on 400 sheep sera, 200 were collected from sheep raised on open grazing system by local farmers in the adjoining areas of Civil Veterinary Dispensaries (CVDs) of range-ecological zone i.e. tehsil Kot Chutta (Dera Ghazi khan). Similarly, the remaining 200 were collected from agro-ecological zone i.e. tehsil Sharaqpur (Sheikhupura), to evaluate the comparative efficacy of LAT with optimized ELISA kit and newly optimized ELISA kit with commercial ELISA kit. FINDINGS The newly ELISA kit optimized against a commercial ELISA kit was found to have 100% sensitivity, 97.6% specificity with 98% Positive Predictive Value, 100% Negative Predictive Value, Cut off value = 0.505, 28.28 LR+, 0.0104 LR-, and 2719.23 DOR. Seroprevalence of toxoplasmosis was detected significantly (P < 0.01; χ2) higher in Sharaqpur (44.5% by LAT; 35.5% by ELISA) as compared to that in Kot Chutta (39.5% by LAT; 31% by ELISA). The highest seroprevalence was seen in the sheep of the 1-2 years age group (P < 0.01; χ2), whereas the lowest in the oldest animals (≥ 4 years). Investigation of meteorological data of both the regions reveals that the zone with higher seroprevalence has relatively higher rainfall, higher humidity, lower environmental temperatures, and higher altitude as the critical factors, potentially behind the significant difference seen in seroprevalence level. The partial correlation of both tests (newly optimized ELISA kit and LAT) was 0.991 at maximum temperature in Sharaqpur while it was 0.981 in Kot Chutta. INTERPRETATION A novel significant correlation was found between the meteorological parameters (relative humidity, minimum, maximum, and average temperatures) divided into yearly units of both the ecological zones, and year-wise seroprevalence (birth years of age-wise groups) of the corresponding regions. We hypothesize that such environmental conditions increase the risk of toxoplasmosis in grazing sheep, owing to a more favorable environment for coccidian oocyst survival. The ELISA kit optimized in this study will be helpful for the detection of seroprevalence of ovine toxoplasmosis in other ecological zones of Pakistan as well as of any other country in the world. More studies are recommended involving regions from other ecological zones of Pakistan to further explore the seroprevalence of ovine toxoplasmosis and to ratify the novel correlation of meteorological parameters with seroprevalence.
Collapse
Affiliation(s)
- Sarfraz Ur Rahman
- Faculty of Veterinary Science, Department of Parasitology, Molecular Parasitology Laboratory, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Haroon Akbar
- Faculty of Veterinary Science, Department of Parasitology, Molecular Parasitology Laboratory, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | | | - Ubaid Ullah
- Faculty of Veterinary Science, Department of Parasitology, Molecular Parasitology Laboratory, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Muhammad Imran Rashid
- Faculty of Veterinary Science, Department of Parasitology, Molecular Parasitology Laboratory, University of Veterinary and Animal Sciences, Lahore, Pakistan
| |
Collapse
|
4
|
Abraham S, Piarroux R, Zhou Y, Tesic V, Abeleda A, Houhou-Fidouh N, Nicaise-Rolland P, Landraud L, McLeod R, Houzé S. Performances of ICT Toxoplasma IgG-IgM test in comparison with Vidas® toxo competition to determine the immune status against Toxoplasma gondii. Eur J Clin Microbiol Infect Dis 2023; 42:1327-1335. [PMID: 37749274 DOI: 10.1007/s10096-023-04669-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/18/2023] [Indexed: 09/27/2023]
Abstract
Toxoplasmosis is a ubiquitous parasitic infection caused by Toxoplasma gondii (Tg). In immunocompetent people, the infection may be asymptomatic with the induction of an immune response that may prevent reinfection or transmission to the fetus in immune pregnant woman. In immunocompromised persons or seronegative pregnant woman with a primary infection during pregnancy, the infection may result in the loss of life, sight, cognition, and motor function in the immune-compromised person or immunologically immature fetus. The objective of this study was to evaluate a new immunochromatographic test Toxoplasma ICT IgG-IgM (ICT) that allows detection of specific anti-Tg immunoglobulins G (Ig G) and M (Ig M). We included 1145 prospectively obtained sera and 376 samples selected for specificity or sensitivity studies. The performance of ICT was compared using Vidas® Toxo Competition (TXC) and Toxoscreen®. In case of discrepancy, Vidas® Toxo Ig G or Ig M and LDBIO Toxo II IgG western blot were used to establish definitive results by additional methods. Sensitivity and specificity of ICT were respectively 99.3% and 100%. In comparison, Toxoscreen®'s sensitivity was 100% and the specificity was 99.8%. TXC had a sensitivity of 98.7% with a specificity of 99.1%. ICT has excellent performance even for low Ig G titers, especially in immunocompromised patients, and confirms the specificity of isolated Ig M. This ICT provides reliable results easily and quickly. This screening technique is not designed to differentiate the Ig M from Ig G. When positive, additional tests may be necessary.
Collapse
Affiliation(s)
- Sylvie Abraham
- Laboratory of Parasitology, Toxoplasma National Reference Center, Bichat-Claude Bernard Hospital, APHP Nord, 46 Rue Henri Huchard, 75018, Paris, France
| | - Raphael Piarroux
- LD Bio Diagnostics, Lyon, France
- Efor-CVO, Champagne Aux Monts d'Or, France
| | - Ying Zhou
- Department of Ophthalmology and Visual Sciences, The University of Chicago, Chicago, IL, USA
- Toxoplasmosis Center, The University of Chicago, AMB N310, Chicago, IL, USA
| | - Vera Tesic
- Department of Pathology, The University of Chicago, Chicago, IL, USA
| | - Ana Abeleda
- Department of Pathology, The University of Chicago, Chicago, IL, USA
| | - Nadhira Houhou-Fidouh
- Laboratory of Virology, Bichat-Claude Bernard Hospital, APHP Nord, 46 Rue Henri Huchard, 75018, Paris, France
| | - Pascale Nicaise-Rolland
- Laboratory of Immunology, Bichat-Claude Bernard Hospital, APHP Nord, 46 Rue Henri Huchard, 75018, Paris Paris, France
| | - Luce Landraud
- Laboratory of Microbiology, Louis Mourier Hospital, APHP Nord, 178 Rue Des Renouillers, 92700, Colombes, France
| | - Rima McLeod
- Department of Ophthalmology and Visual Sciences, The University of Chicago, Chicago, IL, USA
- Toxoplasmosis Center, The University of Chicago, AMB N310, Chicago, IL, USA
- Department of Pediatrics, Division of Infectious Diseases, The University of Chicago, Chicago, IL, USA
| | - Sandrine Houzé
- Laboratory of Parasitology, Toxoplasma National Reference Center, Bichat-Claude Bernard Hospital, APHP Nord, 46 Rue Henri Huchard, 75018, Paris, France.
- Université Paris Cité, IRD, 75006, MERITParis, France.
| |
Collapse
|
5
|
Zhou Y, Leahy K, Grose A, Lykins J, Siddiqui M, Leong N, Goodall P, Withers S, Ashi K, Schrantz S, Tesic V, Abeleda AP, Beavis K, Clouser F, Ismail M, Christmas M, Piarroux R, Limonne D, Chapey E, Abraham S, Baird I, Thibodeau J, Boyer K, Torres E, Conrey S, Wang K, Staat MA, Back N, Gomez Marin J, Peyron F, Houze S, Wallon M, McLeod R. Novel paradigm enables accurate monthly gestational screening to prevent congenital toxoplasmosis and more. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.04.26.23289132. [PMID: 37162985 PMCID: PMC10168490 DOI: 10.1101/2023.04.26.23289132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Background Congenital toxoplasmosis is a treatable, preventable disease, but untreated causes death, prematurity, loss of sight, cognition and motor function, and substantial costs worldwide. Methods/Findings In our ongoing USA feasibility/efficacy clinical trial, data collated with other ongoing and earlier published results proved high performance of an Immunochromatographic-test(ICT) that enables accurate, rapid diagnosis/treatment, establishing new paradigms for care. Overall results from patient blood and/or serum samples tested with ICT compared with gold-standard-predicate-test results found ICT performance for 4606 sera/1876 blood, 99.3%/97.5% sensitive and 98.9%/99.7% specific. However, in the clinical trial the FDA-cleared-predicate test initially caused practical, costly problems due to false-positive-IgM results. For 58 persons, 3/43 seronegative and 2/15 chronically infected persons had false positive IgM predicate tests. This caused substantial anxiety, concerns, and required costly, delayed confirmation in reference centers. Absence of false positive ICT results contributes to solutions: Lyon and Paris France and USA Reference laboratories frequently receive sera with erroneously positive local laboratory IgM results impeding patient care. Therefore, thirty-two such sera referred to Lyon's Reference laboratory were ICT-tested. We collated these with other earlier/ongoing results: 132 of 137 USA or French persons had false positive local laboratory IgM results identified correctly as negative by ICT. Five false positive ICT results in Tunisia and Marseille, France, emphasize need to confirm positive ICT results with Sabin-Feldman-Dye-test or western blot. Separate studies demonstrated high performance in detecting acute infections, meeting FDA, CLIA, WHO ASSURED, CEMark criteria and patient and physician satisfaction with monthly-gestational-ICT-screening. Conclusions/Significance This novel paradigm using ICT identifies likely false positives or raises suspicion that a result is truly positive, rapidly needing prompt follow up and treatment. Thus, ICT enables well-accepted gestational screening programs that facilitate rapid treatment saving lives, sight, cognition and motor function. This reduces anxiety, delays, work, and cost at point-of-care and clinical laboratories. Author’s Summary Toxoplasmosis is a major health burden for developed and developing countries, causing damage to eyes and brain, loss of life and substantial societal costs. Prompt diagnosis in gestational screening programs enables treatment, thereby relieving suffering, and leading to > 14-fold cost savings for care. Herein, we demonstrate that using an ICT that meets WHO ASSURED-criteria identifying persons with/without antibody to Toxoplasma gondii in sera and whole blood with high sensitivity and specificity, is feasible to use in USA clinical practice. We find this new approach can help to obviate the problem of detection of false positive anti- T.gondii IgM results for those without IgG antibodies to T.gondii when this occurs in present, standard of care, predicate USA FDA cleared available assays. Thus, this accurate test facilitates gestational screening programs and a global initiative to diagnose and thereby prevent and treat T.gondii infection. This minimizes likelihood of false positives (IgG and/or IgM) while maintaining maximum sensitivity. When isolated IgM antibodies are detected, it is necessary to confirm and when indicated continue follow up testing in ∼2 weeks to establish seroconversion. Presence of a positive ICT makes it likely that IgM is truly positive and a negative ICT makes it likely that IgM will be a false positive without infection. These results create a new, enthusiastically-accepted, precise paradigm for rapid diagnosis and validation of results with a second-line test. This helps eliminate alarm and anxiety about false-positive results, while expediting needed treatment for true positive results and providing back up distinguishing false positive tests.
Collapse
|
6
|
Akbar H, Shabbir MZ, Ullah U, Rashid MI. Serological Investigation of Bovine Toxoplasmosis Using Commercial and Indigenous ELISA Kits While Validating Cattle Toxo IgG ELISA Kit. Animals (Basel) 2022; 12:ani12162067. [PMID: 36009657 PMCID: PMC9405383 DOI: 10.3390/ani12162067] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/23/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Toxoplasmosis is a zoonotic disease caused by T. gondii infection. The main aims of this study were to assess the seropositivity to toxoplasmosis of an exotic breed of cattle (n = 400) from different farms using the Latex Agglutination Test, validate the Cattle Toxo IgG ELISA kit with the help of the commercially available ELISA kit and compare the efficacy of the LAT and Cattle Toxo IgG ELISA kit for assessing seropositivity of cattle to toxoplasmosis. Four hundred cattle sera were collected from an exotic breed of cattle in Pakistan. These sera were evaluated through an LAT and Cattle Toxo IgG ELISA kit. Of 400 samples, 90 were elected and screened through a commercially available ELISA kit. The sensitivity and specificity of the Cattle Toxo IgG ELISA kit came out to be 100% and 96.15%, and in LAT, it was found as 26.31% and 61.53%, respectively. The Cattle Toxo IgG ELISA kit revealed 29.75% (119/400) seropositivity, 6% less than that found through LAT. The results of this study show that Cattle Toxo IgG ELISA kit is a highly accurate and reliable serodiagnostic tool to diagnose bovine toxoplasmosis. Abstract Toxoplasma gondii is a protozoan parasite that causes toxoplasmosis in warm-blooded vertebrates, globally. The main aims of this study were to assess the seropositivity to toxoplasmosis of an exotic breed of cattle (n = 400) from different farms using the Latex Agglutination Test and validate Cattle Toxo IgG ELISA kit. Of a total of 400 cattle sera that were evaluated by LAT, 143 (35.75%) were found positive. Based on these data, 90 samples (n = 60 seronegative by LAT; n = 30 seropositive by LAT) were elected for screening through a commercially available ELISA kit. The same 90 samples were screened through a Cattle Toxo IgG ELISA kit for validation purposes. Of 90 samples, 40 were seropositive in the Cattle Toxo IgG ELISA kit (100% sensitivity), and 38 were seropositive in a commercially available ELISA kit. All 50 samples in the Cattle Toxo IgG ELISA kit (96.15% specificity) were also seronegative in the commercially available ELISA kit. Hence, the sensitivity and specificity of the Cattle Toxo IgG ELISA kit came out to be 100% and 96.15%, and in LAT, it was found as 26.31% and 61.53%, respectively. Therefore, the Cattle Toxo IgG ELISA kit is a highly reliable serodiagnostic tool to diagnose bovine toxoplasmosis.
Collapse
Affiliation(s)
- Haroon Akbar
- Department of Parasitology, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan
- Correspondence: (S.-u.-R.); (H.A.)
| | - Muhammad Zubair Shabbir
- Institute of Microbiology, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan
| | - Ubaid Ullah
- Department of Parasitology, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan
| | - Muhammad Imran Rashid
- Department of Parasitology, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan
| |
Collapse
|
7
|
Meroni V, Genco F, Scudeller L, Brenier-Pinchart MP, Fricker-Hidalgo H, L’Ollivier C, Paris L, Pelloux H. Diagnostic Accuracy of LDBIO-Toxo II IgG and IgM Western Blot in Suspected Seroconversion in Pregnancy: A Multicentre Study. Pathogens 2022; 11:pathogens11060665. [PMID: 35745519 PMCID: PMC9231380 DOI: 10.3390/pathogens11060665] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/08/2022] [Indexed: 02/01/2023] Open
Abstract
The high sensitivity of the automated tests used for Toxoplasma gondii serology can yield false-positive IgM results due to aspecific reactions. On the other hand, specific therapy can delay IgG production and, therefore, the diagnosis of seroconversion. There is a need for confirmation tests to early detect seroconversions during pregnancy. We conducted a multicentre study to evaluate the diagnostic accuracy of the Toxo II IgG and a new, not yet commercialised Toxo II IgM western blot (WB) (LDBio diagnostics Lyon France) on 229 sera corresponding to 93 patients with seroconversions and 158 sera corresponding to 68 patients with nonspecific IgM. Sensitivity was 97.8% for IgM WB and 98.9% for IgG WB. Specificity was 89.7% and 100%, respectively. The concordance between IgM and IgG Toxo WB with the final diagnosis was very good, K = 0.89 and K = 0.99, respectively. In 5 cases (5.4%), the appearance of IgM, and in 55 cases (59.1%), the appearance of IgG was recorded by WB earlier than by traditional tests. In 10 cases (10.8%), IgM was detected after the traditional tests and in 2 cases (2.2%) for IgG. The association of IgG and IgM WB on the same sample not only detected all seroconversions but also correctly identified most of the false-positive results.
Collapse
Affiliation(s)
- Valeria Meroni
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy;
| | - Francesca Genco
- Microbiology and Virology Unit, Fondazione IRCCS San Matteo Hospital Foundation, 27100 Pavia, Italy;
| | - Luigia Scudeller
- UOC Innovation and Research, IRCCS University Hospital Sant’Orsola, 40138 Bologna, Italy;
| | - Marie-Pierre Brenier-Pinchart
- Parasitology-Mycology, University Hospital and Grenoble-Alpes University, 38043 Grenoble, France; (M.-P.B.-P.); (H.F.-H.); (H.P.)
| | - Hélène Fricker-Hidalgo
- Parasitology-Mycology, University Hospital and Grenoble-Alpes University, 38043 Grenoble, France; (M.-P.B.-P.); (H.F.-H.); (H.P.)
| | - Coralie L’Ollivier
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, IHU Méditerranée, 13005 Marseille, France;
| | - Luc Paris
- APHP-Sorbonne Université, Parasitology-Mycology, Pitié-Salpêtrière Hospital, 75013 Paris, France
- Correspondence: ; Tel.: +33-(0)1-42-16-01-60
| | - Hervé Pelloux
- Parasitology-Mycology, University Hospital and Grenoble-Alpes University, 38043 Grenoble, France; (M.-P.B.-P.); (H.F.-H.); (H.P.)
| |
Collapse
|
8
|
Olsen A, Nielsen HV, Alban L, Houe H, Jensen TB, Denwood M. Determination of an optimal ELISA cut-off for the diagnosis of Toxoplasma gondii infection in pigs using Bayesian latent class modelling of data from multiple diagnostic tests. Prev Vet Med 2022; 201:105606. [DOI: 10.1016/j.prevetmed.2022.105606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/14/2022] [Accepted: 02/26/2022] [Indexed: 11/27/2022]
|
9
|
Jean-Pierre V, Miozzo J, Fricker-Hidalgo H, Garnaud C, Robert MG, Pelloux H, Brenier-Pinchart MP. Serological diagnosis of toxoplasmosis: evaluation of the commercial test recomLine Toxoplasma IgG immunoblot (Mikrogen) based on recombinant antigens. Parasite 2022; 29:52. [PMCID: PMC9645231 DOI: 10.1051/parasite/2022050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 10/06/2022] [Indexed: 11/11/2022] Open
Abstract
Background: IgG detection to determine immune status to Toxoplasma gondii infection and seroconversion mainly relies on ELISA techniques and, if necessary, on a confirmatory test, Western blot. This study evaluated the performance of the recomLine Toxoplasma IgG immunoblot (IB-recomLine) (Mikrogen) as a confirmatory test on a large number of sera. A total of 171 sera were selected (113 patients) and had previously been analyzed by two ELISA tests, ARCHITECT (Abbott) and VIDAS (bioMérieux) ± LDBIO-Toxo II IgG Western blot (WB-LDBIO) (LDBio). The sera were classified into three groups: group 1 included 50 sera without difficulty in interpreting the IgG results (patients with documented past infection or uninfected); group 2 included 47 sera with difficulty in interpreting the ELISA results; and group 3 included 74 sequential sera from 25 pregnant women with seroconversion. Results: In group 1, overall IgG agreements were 94% and 90% with ARCHITECT and VIDAS, respectively. In group 2, low agreement was observed between IB-recomLine and WB-LDBIO, with eight false-positive and 13 false-negative results. In group 3, 4/13 seroconversions were detected earlier with IB-recomLine compared to other tests. Conclusions: IB-recomLine allowed for earlier diagnosis of toxoplasmic seroconversion compared to both ELISA tests and WB-LDBIO but led to insufficient performance to confirm the immune status when ELISA results were discordant or equivocal.
Collapse
Affiliation(s)
- Vincent Jean-Pierre
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
- Corresponding author:
| | - Julien Miozzo
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
| | | | - Cécile Garnaud
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
- TIMC, CNRS, Université Grenoble Alpes 38000 Grenoble France
| | - Marie Gladys Robert
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
| | - Hervé Pelloux
- Parasitology-Mycology, Grenoble Alpes University Hospital 38000 Grenoble France
| | | |
Collapse
|
10
|
Development of Human Toxo IgG ELISA Kit, and False-Positivity of Latex Agglutination Test for the Diagnosis of Toxoplasmosis. Pathogens 2021; 10:pathogens10091111. [PMID: 34578144 PMCID: PMC8465318 DOI: 10.3390/pathogens10091111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/19/2022] Open
Abstract
Toxoplasma gondii is an intracellular zoonotic parasite that causes infection in a wide range of warm-blooded animals and humans. The main aim of this study was to assess the diagnostic value of the recombinant SAG1 antigen (rSAG1) for T. gondii-IgG screening through the Human Toxo IgG ELISA Kit (K). The rSAG1 was expressed in E. coli (DE3), and it was purified through metal-affinity chromatography. The rSAG1 was confirmed by immunoblotting, and it had a band on 35 kDa. Total of 400 human sera were tested by LAT and K. One hundred and twenty-two (30.5%) sera were found positive by LAT and eighty-nine (22.25%) sera were found positive by K. Out of 400 samples, 80 were selected to evaluate the performance of K through commercial Toxoplasma gondii IgG ELISA Kit (C). Out of 80 human sera, 55 (68.75%) were found positive, 25 (31.25%) were found negative by K and C, respectively. The cut-off value for K was 0.398 and it was calculated through the receiver operator characteristic curve. The ELISA plates were coated at optimized concentration of rSAG1 = 0.125 µg/mL, and the test was performed by diluting the sera at 1:50. The sensitivity and specificity of K were observed to be 98.5% and 100%, respectively. The six sera (K−L+) were found positive through LAT and these human sera were later evaluated by Western blot analysis. These sera did not produce a band equivalent to 35 kDa on WB analysis thus, LAT produced false-positive results.
Collapse
|
11
|
Olsen A, Alban L, Denwood M, Houe H, Birk Jensen T, Vedel Nielsen H. A longitudinal study of Toxoplasma gondii seroconversion on four large Danish sow farms. Vet Parasitol 2021; 295:109460. [PMID: 34029851 DOI: 10.1016/j.vetpar.2021.109460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 11/26/2022]
Abstract
Serological tests are routinely used to detect Toxoplasma gondii specific IgG antibodies in serum. Serological surveys of T. gondii show a medium to high prevalence in Danish indoor sows at the time of slaughter. However, little is known about when sows acquire T. gondii, and for how long they remain seropositive. Our focus was on quantifying the incidence rates in different age-cohorts and on investigating the T. gondii IgG antibody dynamics in sows. Four large Danish sow farms were longitudinally surveyed for 1 year. A total of 320 animals from 6, 12, 18, and 24-months age-cohorts were sampled at 5-week intervals. In total, 2989 plasma samples were tested using commercial enzyme linked immunosorbent assay (ELISA). The incidence rate in each of the four age-cohorts was calculated, and a time-to-event analysis was applied to the interval censored data to investigate the relationship between age and probability of T. gondii seroconversion. In the initial ELISA testing, eight sows tested positive for T. gondii at first survey, of which seven remained seropositive throughout the follow-up period. Additionally, 16 sows seroconverted, but only five of these remained seropositive. Weekly incidence rates in the 6, 12, 18, and 24-month age-cohorts were 0.0017 (95% CI = 0.0008 - 0.0037), 0.0009 (95% CI = 0.0003 - 0.0027), 0.0003 (95% CI = 0.0000 - 0.0018), and 0.0023 (95% CI = 0.0010 - 0.0051), respectively. Time-to-event analysis suggested that the incidence rate increased with age but could not conclude this definitively. The retesting of a subsample of the sows (n = 200) with the same ELISA and with modified direct agglutination test (MAT), and western blot (WB) assays suggested that 12 out of the 24 initial ELISA seropositive sows may have been false positive. These 12 sows also showed fluctuating antibody dynamics in ELISA. Hence, the unstable antibody dynamics in ELISA may pose a challenge for serological surveys of T. gondii in sows.
Collapse
Affiliation(s)
- Abbey Olsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Denmark; Department of Food Safety, Veterinary Issues & Risk Analysis, Danish Agriculture & Food Council, Axelborg, Axeltorv 3, DK-1609, Copenhagen, Denmark.
| | - Lis Alban
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Denmark; Department of Food Safety, Veterinary Issues & Risk Analysis, Danish Agriculture & Food Council, Axelborg, Axeltorv 3, DK-1609, Copenhagen, Denmark.
| | - Matthew Denwood
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Denmark.
| | - Hans Houe
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870, Frederiksberg C, Denmark.
| | | | - Henrik Vedel Nielsen
- Laboratory of Parasitology, Department of Bacteria, Parasites & Fungi, Infectious Disease Preparedness, Statens Serum Institut, Artillerivej 5, DK-2300, Copenhagen S, Denmark.
| |
Collapse
|
12
|
Rym B, Yasmine K, Hedia B, Nesrine I, Olfa S, Rania M, Karim A, Aïda B. Contribution of the Toxoplasma ICT IgG IgM ® test in determining the immune status of pregnant women against toxoplasmosis. J Clin Lab Anal 2021; 35:e23749. [PMID: 33720427 PMCID: PMC8128306 DOI: 10.1002/jcla.23749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/08/2021] [Accepted: 02/17/2021] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND An immunochromatography technology (ICT) rapid diagnostic test, the Toxoplasma ICT IgG-IgM® , was recently developed. Our aim was to study its contribution to establish accurately the Toxoplasma immune status in Tunisian pregnant women using Western blot (WB) Toxo II IgG® as a reference technique. METHODS Thirty-nine sera were selected for the study from among 2,615 which were already tested by IgG and IgM ELISA. They displayed equivocal IgG titres (4.4-9 IU/ml) in absence of IgM (19 sera) or IgM anti-Toxoplasma antibodies in absence of IgG (titre <4.4 IU/ml) (20 sera). All these sera were additionally tested by WB Toxo II IgG® . RESULTS Immunochromatography technology Sensitivity in the detection either of low IgG titres in absence of IgM or of specific anti-Toxoplasma IgM was 100%. Only one serum with equivocal IgG titre by ELISA and negative with Toxo II IgG® test revealed positive in ICT. However, this serum showed a P30 band in WB analysis. On the other hand, three sera positive in ELISA IgM and negative in ELISA IgG revealed positive in ICT and negative in WB Toxo II IgG® , the reference test. CONCLUSION Results confirm the high sensitivity of Toxoplasma ICT IgG-IgM® in detecting both specific anti-Toxoplasma IgG and IgM, and highlight the usefulness of this rapid test as a first or second-line Toxoplasma serological test in pregnant women.
Collapse
Affiliation(s)
- Ben‐Abdallah Rym
- Department of ParasitologyPasteur Institute of TunisTunisTunisia
- Research Laboratory Medical Parasitology, Biotechnology and Biomolecule LR 11IPT‐06Pasteur Institute of TunisUniversity Tunis El‐ManarTunisTunisia
| | | | - Bellali Hedia
- Department of EpidemiologyAbderrahmane Mami HospitalArianaTunisia
| | - Issaoui Nesrine
- Department of ParasitologyPasteur Institute of TunisTunisTunisia
| | - Souissi Olfa
- Department of ParasitologyPasteur Institute of TunisTunisTunisia
| | - Maatoug Rania
- Department of ParasitologyPasteur Institute of TunisTunisTunisia
| | - Aoun Karim
- Department of ParasitologyPasteur Institute of TunisTunisTunisia
- Research Laboratory Medical Parasitology, Biotechnology and Biomolecule LR 11IPT‐06Pasteur Institute of TunisUniversity Tunis El‐ManarTunisTunisia
| | - Bouratbine Aïda
- Department of ParasitologyPasteur Institute of TunisTunisTunisia
- Research Laboratory Medical Parasitology, Biotechnology and Biomolecule LR 11IPT‐06Pasteur Institute of TunisUniversity Tunis El‐ManarTunisTunisia
| |
Collapse
|
13
|
Robert-Gangneux F, Guegan H. Anti-Toxoplasma IgG assays: What performances for what purpose? A systematic review. Parasite 2021; 28:39. [PMID: 33904818 PMCID: PMC8078101 DOI: 10.1051/parasite/2021035] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/31/2021] [Indexed: 12/27/2022] Open
Abstract
Chronic infection with Toxoplasma gondii is attested by the detection of specific anti-Toxoplasma IgG. A wide panel of serologic methods is currently marketed, and the most suitable method should be chosen according to the laboratory resources and the screened population. This systematic review of evaluation studies aimed at establishing an overview of the performances, i.e. sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of marketed anti-Toxoplasma IgG assays, and discussing their technical characteristics to guide further choice for routine diagnostic use. According to PRISMA guidelines, the search performed in PubMed and Web of Science databases recovered 826 studies, of which 17 were ultimately included. Twenty commercial anti-Toxoplasma IgG assays were evaluated, in comparison with an accepted reference method. Most of them were enzyme-immunoassays (EIAs, n = 12), followed by agglutination tests (n = 4), immunochromatographic tests (n = 3), and a Western-Blot assay (WB, n = 1). The mean sensitivity of IgG assays ranged from 89.7% to 100% for standard titers and from 13.4% to 99.2% for low IgG titers. A few studies pointed out the ability of some methods, especially WB to detect IgG early after primary infection. The specificity of IgG assays was generally high, ranging from 91.3% to 100%; and higher than 99% for most EIA assays. The PPV was not a discriminant indicator among methods, whereas significant disparities (87.5%-100%) were reported among NPVs, a key-parameter assessing the ability to definitively rule out a Toxoplasma infection in patients at-risk for opportunistic infections.
Collapse
Affiliation(s)
- Florence Robert-Gangneux
-
Université de Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé Environnement Travail), UMR_S 1085 35000 Rennes France
| | - Hélène Guegan
-
Université de Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé Environnement Travail), UMR_S 1085 35000 Rennes France
| |
Collapse
|
14
|
Dard C, Swale C, Brenier-Pinchart MP, Farhat DC, Bellini V, Robert MG, Cannella D, Pelloux H, Tardieux I, Hakimi MA. A brain cyst load-associated antigen is a Toxoplasma gondii biomarker for serodetection of persistent parasites and chronic infection. BMC Biol 2021; 19:25. [PMID: 33557824 PMCID: PMC7871634 DOI: 10.1186/s12915-021-00959-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 01/12/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Biomarker discovery remains a major challenge for predictive medicine, in particular, in the context of chronic diseases. This is true for the widespread protozoan Toxoplasma gondii which establishes long-lasting parasitism in metazoans, humans included. This microbe successively unfolds distinct genetic programs that direct the transition from high to low replicative potential inside host cells. As a slow-replicating cell, the T. gondii bradyzoite developmental stage persists enclosed in a cyst compartment within tissues including the nervous system, being held by a sustained immune equilibrium which accounts for the prolonged clinically silent phase of parasitism. Serological surveys indicate that nearly one third of the human population has been exposed to T. gondii and possibly host bradyzoites. Because any disruption of the immune balance drives the reverse transition from bradyzoite to fast replicating tachyzoite and uncontrolled growth of the latter, these people are at risk for life-threatening disease. While serological tests for discriminating recent from past infection are available, there is yet no immunogenic biomarker used in the serological test to allow ascertaining the presence of persistent bradyzoites. RESULTS Capitalizing on genetically engineered parasites induced to produce mature bradyzoites in vitro, we have identified the BCLA/MAG2 protein being restricted to the bradyzoite and the cyst envelope. Using laboratory mice as relevant T. gondii host models, we demonstrated that BCLA/MAG2 drives the generation of antibodies that recognize bradyzoite and the enveloping cyst structure. We have designed an ELISA assay based on a bacterially produced BCLA recombinant polypeptide, which was validated using a large collection of sera from mice of different genetic backgrounds and infected with bcla+ or bcla-null cystogenic and non-cystogenic T. gondii strains. To refine the design of the ELISA assay, we applied high-resolution BCLA epitope mapping and identified a specific combination of peptides and accordingly set up a selective and sensitive ELISA assay which allowed the detection of anti-BCLA/MAG2 antibodies in the sera of human patients with various forms of toxoplasmosis. CONCLUSIONS We brought proof of principle that anti-BCLA/MAG2 antibodies serve as specific and sensitive serological markers in the perspective of a combinatorial strategy for detection of persistent T. gondii parasitism.
Collapse
Affiliation(s)
- Céline Dard
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
- Laboratory of Parasitology and Mycology, Grenoble Alpes University Hospital, CS10217, 38043, Grenoble, France
| | - Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Marie-Pierre Brenier-Pinchart
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
- Laboratory of Parasitology and Mycology, Grenoble Alpes University Hospital, CS10217, 38043, Grenoble, France
| | - Dayana C Farhat
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Valeria Bellini
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Marie Gladys Robert
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
- Laboratory of Parasitology and Mycology, Grenoble Alpes University Hospital, CS10217, 38043, Grenoble, France
| | - Dominique Cannella
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Hervé Pelloux
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
- Laboratory of Parasitology and Mycology, Grenoble Alpes University Hospital, CS10217, 38043, Grenoble, France
| | - Isabelle Tardieux
- Team Membrane and Cell Dynamics of Host Parasite Interactions, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Mohamed-Ali Hakimi
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France.
| |
Collapse
|
15
|
Xin S, Su R, Jiang N, Zhang L, Yang Y. Low Prevalence of Antibodies Against Toxoplasma gondii in Chinese Populations. Front Cell Infect Microbiol 2020; 10:302. [PMID: 32656100 PMCID: PMC7324674 DOI: 10.3389/fcimb.2020.00302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/20/2020] [Indexed: 11/29/2022] Open
Abstract
Toxoplasma gondii has been found to infect almost all warm-blooded animals, including humans. In this study, a total of 3,275 human serum samples were collected from hospitals in five provinces of China. About 5.13% (168/3,275) (95% CI, 4.42–5.94) of the serum samples tested positive for T. gondii IgG antibody by a modified agglutination test (MAT) (cut-off: 1:20). Significant associations were detected between geographic location (OR = 1.763), age (OR = 3.072), infertility in women (OR = 2.4409) and T. gondii infection in humans (p < 0.05). To minimize infection, citizens need to be informed about the best practices for toxoplasmosis prevention, including eating well-cooked meat, drinking boiled water, washing vegetables and fruits, and being careful during contact with cats.
Collapse
Affiliation(s)
- Shilin Xin
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Ruijing Su
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Nan Jiang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Longxian Zhang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| | - Yurong Yang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China
| |
Collapse
|
16
|
Simon L, Fillaux J, Guigon A, Lavergne RA, Villard O, Villena I, Marty P, Pomares C. Serological diagnosis of Toxoplasma gondii: analysis of false-positive IgG results and implications. Parasite 2020; 27:7. [PMID: 32031519 PMCID: PMC7006501 DOI: 10.1051/parasite/2020006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 01/29/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Primary infection by Toxoplasma gondii in pregnant women can result in serious outcomes for the foetus. A false-positive IgG result during pregnancy can lead to a misdiagnosis of past infection and to stopping preventive measures. We collected 189 sera with positive Architect® Toxo IgG assay (Abbott Laboratories) and negative IgG results with at least two other serological tests, in order to find an explanation for the suspected false-positive IgG results. We used the recomLine Toxoplasma IgG® immunoblot (Mikrogen Diagnostik) to search for specific antigenic reactivities of the sera, and the LDBio Toxo II IgG® immunoblot (LDBio Diagnostics) as a confirmatory test. RESULTS The bands GRA8 and/or GRA7 were positive for 148 samples (78.3%). GRA8 was the most frequent band, appearing in 133 patterns (70.4%), whereas GRA7 was present for 49 samples (25.9%). Of the 81 samples tested with LDBio®, 23 (28.4%) turned out to be positive. Of the 58 negative LDBio® tests (71.6%) (real false-positive Architect® IgG), 23 samples (39.6%) did not show either a GRA8 or p30 band by recomLine®. Their false positivity with Architect® remains unexplained since Abbott uses these two recombinant antigens for their assay. CONCLUSIONS The Architect® IgG false positivity for T. gondii seems to be due to reactivity against GRA8 for the majority of the sera and GRA7 to a lesser extent. The hypothesis of past contact with parasites genetically close to T. gondii such as Hammondia hammondi or Neospora caninum seems promising and should be assessed further.
Collapse
Affiliation(s)
- Loïc Simon
-
Service de Parasitologie-Mycologie, CHU de Nice, Université Côte d’Azur 06202 Nice France
-
Inserm U1065, C3M 06204 Nice France
| | - Judith Fillaux
-
Service de Parasitologie-Mycologie, CHU de Toulouse 31300 Toulouse France
-
PharmaDev, IRD UMR 152, Université de Toulouse 31062 Toulouse France
| | - Aurélie Guigon
-
Service de Microbiologie, Hôpital La Source, CHR d’Orléans 45100 Orléans France
| | - Rose-Anne Lavergne
-
Parasitologie-Mycologie, CHU de Nantes 44093 Nantes France
-
Université de Nantes, Nantes Atlantique Universités, EA1155-IICiMed, Institut de Recherche en Santé 2 44200 Nantes France
| | - Odile Villard
-
Institut de Parasitologie et de Pathologie Tropicale, EA 7292, Fédération de Médecine Translationnelle, Université de Strasbourg 67000 Strasbourg France
| | - Isabelle Villena
-
EA7510, ESCAPE, Laboratoire de Parasitologie-Mycologie, Université de Reims Champagne-Ardenne, SFR Cap Santé FED 4231 51096 Reims France
| | - Pierre Marty
-
Service de Parasitologie-Mycologie, CHU de Nice, Université Côte d’Azur 06202 Nice France
-
Inserm U1065, C3M 06204 Nice France
| | - Christelle Pomares
-
Service de Parasitologie-Mycologie, CHU de Nice, Université Côte d’Azur 06202 Nice France
-
Inserm U1065, C3M 06204 Nice France
| |
Collapse
|
17
|
Performance of Zika Assays in the Context of Toxoplasma gondii, Parvovirus B19, Rubella Virus, and Cytomegalovirus (TORCH) Diagnostic Assays. Clin Microbiol Rev 2019; 33:33/1/e00130-18. [PMID: 31826871 DOI: 10.1128/cmr.00130-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Infections during pregnancy that may cause congenital abnormalities have been recognized for decades, but their diagnosis is challenging. This was again illustrated with the emergence of Zika virus (ZIKV), highlighting the inherent difficulties in estimating the extent of pre- and postnatal ZIKV complications because of the difficulties in establishing definitive diagnoses. We reviewed the epidemiology, infection kinetics, and diagnostic methods used for Toxoplasma gondii, parvovirus B19, rubella virus, and cytomegalovirus (TORCH) infections and compared the results with current knowledge of ZIKV diagnostic assays to provide a basis for the inclusion of ZIKV in the TORCH complex evaluations. Similarities between TORCH pathogens and ZIKV support inclusion of ZIKV as an emerging TORCH infection. Our review evaluates the diagnostic performance of various TORCH diagnostic assays for maternal screening, fetal screening, and neonatal screening. We show that the sensitivity, specificity, and positive and negative predictive value of TORCH complex pathogens are widely variable, stressing the importance of confirmatory testing and the need for novel techniques for earlier and accurate diagnosis of maternal and congenital infections. In this context it is also important to acknowledge different needs and access to care for different geographic and resource settings.
Collapse
|
18
|
Douet T, Armengol C, Charpentier E, Chauvin P, Cassaing S, Iriart X, Berry A, Fillaux J. Performance of seven commercial automated assays for the detection of low levels of anti-Toxoplasma IgG in French immunocompromised patients. Parasite 2019; 26:51. [PMID: 31441775 PMCID: PMC6707100 DOI: 10.1051/parasite/2019052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/02/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Immunocompromised patients are at high risk for the development of severe toxoplasmosis from tissue cyst reactivation, the most frequently, or from recently acquired acute infections. Knowledge of serologic status is therefore crucial. Screening for toxoplasmosis is sometimes performed while patients are already immunocompromised and have a low or even undetectable IgG titer by routine automated enzyme immunoassays. The aim of this study was to assess the sensitivity and specificity of seven reagents for the detection of low levels of IgG. Sera from 354 patients were collected and analysed. RESULTS Elecsys® offered the best analytic performances, superior to those of Architect® and Platelia®, which were superior to those of Access II® and TGS TA®. Vidas II® and Liaison II® reagents exhibited poor analytical performances in this cohort. For Elecsys®, Platelia® and Architect®, new thresholds for the grey zone and positive zone have been defined to improve the sensitivity of these reagents while maintaining excellent specificity. CONCLUSIONS Commercialized assays for toxoplasmosis screening are not suitable for IgG low-level detection in patients without adapting the supplier thresholds to avoid false negative results and risk generalized toxoplasmosis.
Collapse
Affiliation(s)
- Tiphaine Douet
-
Service de Parasitologie – Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan 330 avenue de Grande Bretagne 31059 Toulouse France
| | - Catherine Armengol
-
Service de Parasitologie – Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan 330 avenue de Grande Bretagne 31059 Toulouse France
-
Laboratoire d’analyse biomédicale, Centre Hospitalier Comminges Pyrénées Avenue de Saint Plancard 31806 Saint Gaudens France
| | - Elena Charpentier
-
Service de Parasitologie – Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan 330 avenue de Grande Bretagne 31059 Toulouse France
| | - Pamela Chauvin
-
Service de Parasitologie – Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan 330 avenue de Grande Bretagne 31059 Toulouse France
| | - Sophie Cassaing
-
Service de Parasitologie – Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan 330 avenue de Grande Bretagne 31059 Toulouse France
-
Pharmacochimie et Biologie Pour le Développement (PHARMA-DEV), IRD UMR 152 Université Paul Sabatier 35 Chemin des Maraîchers 31400 Toulouse France
| | - Xavier Iriart
-
Service de Parasitologie – Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan 330 avenue de Grande Bretagne 31059 Toulouse France
| | - Antoine Berry
-
Service de Parasitologie – Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan 330 avenue de Grande Bretagne 31059 Toulouse France
| | - Judith Fillaux
-
Service de Parasitologie – Mycologie, Centre Hospitalier Universitaire de Toulouse-Purpan 330 avenue de Grande Bretagne 31059 Toulouse France
-
Pharmacochimie et Biologie Pour le Développement (PHARMA-DEV), IRD UMR 152 Université Paul Sabatier 35 Chemin des Maraîchers 31400 Toulouse France
| |
Collapse
|
19
|
Hoshina T, Fukumoto S, Aonuma H, Saiki E, Hori S, Kanuka H. Seroprevalence of Toxoplasma gondii in wild sika deer in Japan. Parasitol Int 2019; 71:76-79. [PMID: 30940609 DOI: 10.1016/j.parint.2019.03.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 12/29/2022]
Abstract
Toxoplasmosis is a food-borne infection that is widespread around the world, causing congenital disorders and opportunistic infections. Ingestion of undercooked meat is one of the risk factors for infection with the causative agent, Toxoplasma gondii. Japanese people occasionally eat rare meat as a traditional cuisine style called "Sashimi". A rapid increase in venison consumption in Japan has occurred mainly due to enhanced population control of wild Japanese deer (Cervus nippon) in recent decades. In particular, Yezo-sika deer (C. n. yesoensis) in Hokkaido (the northernmost and largest prefecture in Japan) is frequently supplied to markets as branded game/bushmeat. To study the possible burden of Toxoplasma gondii among wild Yezo-sika deer, plasma samples of Yezo-sika deer hunted during two seasons, 2010-2012, in Eastern Hokkaido were investigated. A total 80 samples were examined using the Sabin-Feldman dye test, which is highly specific and sensitive for identifying the development and persistence of antibodies after primary Toxoplasma infection, demonstrating that 38 cases (47.5%) were seropositive (cut-off titer <1:16). Antibody prevalence of T. gondii in female deer was higher than in males. Adult deer aged 3 years or over showed higher seroprevalence compared with younger animals. The overall seroprevalence fluctuated significantly according to the season when the deer were hunted. These results indicated widespread infection of T. gondii among Japanese wild Yezo-sika deer, suggesting that both appropriate handling and treatment of bushmeat are required to prevent food-borne toxoplasmosis in Japan.
Collapse
Affiliation(s)
- Tokio Hoshina
- Department of Tropical Medicine, The Jikei University School of Medicine, Tokyo, Japan; Department of Infectious Diseases and Infection Control, The Jikei University School of Medicine, Tokyo, Japan.
| | - Shinya Fukumoto
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan
| | - Hiroka Aonuma
- Department of Tropical Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Erisha Saiki
- Department of Tropical Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Seiji Hori
- Department of Infectious Diseases and Infection Control, The Jikei University School of Medicine, Tokyo, Japan
| | - Hirotaka Kanuka
- Department of Tropical Medicine, The Jikei University School of Medicine, Tokyo, Japan.
| |
Collapse
|
20
|
Sağlam Metiner P, Can H, Ayyıldız Tamiş D, Karakavuk M, Kımız Geboloğlu I, Gülçe İz S, Atalay Şahar E, Değirmenci Döşkaya A, Gürüz Y, Deliloğlu Gürhan Sİ, Döşkaya M. The use of Toxoplasma gondii tachyzoites produced in HeLa cells adhered to Cytodex 1 microcarriers as antigen in serological assays: an application of microcarrier technology. Cytotechnology 2019; 71:91-105. [PMID: 30607647 DOI: 10.1007/s10616-018-0269-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 10/13/2018] [Indexed: 01/01/2023] Open
Abstract
Toxoplasma gondii can infect nearly all warm-blooded animals, including humans. In the laboratory diagnosis of toxoplasmosis, serological tests have importance in detecting antibody response. Traditionally T. gondii tachyzoites grown in vivo are being used as an antigen source in serological assays. Currently, tachyzoites produced in vitro are being tested as an antigen source in order to decrease animal use. Microcarrier technology allowed us to grow anchorage-dependent host cells on microcarrier suspension in short time and approximately 10 times more than traditional flask technique. The ability of T. gondii tachyzoites to grow in host cells adhered to microcarriers has not been analyzed yet. In this study, we aimed to develop a novel in vitro culture method to produce T. gondii tachyzoites abundantly using HeLa cells adhered to Cytodex 1 microcarriers. Initially, the growth of HeLa cells adhered to Cytodex 1 was analyzed using RPMI 1640, DMEM, and EMEM. Next, HeLa cells with a concentration of 1 × 105 cells/ml and 2 × 105 cells/ml were adhered to Cytodex 1 and grown in spinner flasks. Then, T. gondii tachyzoites were inoculated with 1:1 and 2:1 cell:tachyzoite ratios to HeLa cells adhered to microcarriers in spinner flaks. During continuous production in spinner flasks, tachyzoites were harvested at the 2nd, 4th, and 7th day of culture and the quality of antigens produced from these tachyzoites were tested in ELISA and Western Blotting using sera of patients with toxoplasmosis. The optimization studies showed that finest HeLa inoculation value was 2 × 105 cells/ml using RPMI 1640, and the cell:tachyzoite ratio to obtain the highest tachyzoite yield (17.1 × 107) was 1:1 at the 4th day of inoculation. According to the results of ELISA comparing HeLa cell and mouse derived antigens, the highest correlation with mouse antigen was achieved at the 4th day of HeLa cell culture with 1:1 HeLa:tachyzoite ratio (P < 0.0001). The sensitivity and specificity ratios of ELISA were 100%. In addition, Western blotting banding patterns of the antigen derived at the 4th day of HeLa cell culture with 1:1 HeLa:tachyzoite ratio was comparable with mouse derived antigen. Overall, this novel methodology can be an alternative source of antigen in diagnostic assays, decrease animal use for antigen production, and contribute to the solution of ethical and economic problems.
Collapse
Affiliation(s)
- Pelin Sağlam Metiner
- Department of Bioengineering, Faculty of Engineering, Ege University, Bornova, İzmir, Turkey
| | - Hüseyin Can
- Department of Biology, Molecular Biology Section, Faculty of Science, Ege University, Bornova, İzmir, Turkey.
| | - Duygu Ayyıldız Tamiş
- Department of Bioengineering, Faculty of Engineering, Ege University, Bornova, İzmir, Turkey
| | - Muhammet Karakavuk
- Department of Parasitology, Faculty of Medicine, Ege University, Bornova, İzmir, Turkey
| | - Ilgın Kımız Geboloğlu
- Department of Bioengineering, Faculty of Engineering, Ege University, Bornova, İzmir, Turkey
| | - Sultan Gülçe İz
- Department of Bioengineering, Faculty of Engineering, Ege University, Bornova, İzmir, Turkey
| | - Esra Atalay Şahar
- Department of Parasitology, Faculty of Medicine, Ege University, Bornova, İzmir, Turkey
| | | | - Yüksel Gürüz
- Department of Parasitology, Faculty of Medicine, Ege University, Bornova, İzmir, Turkey
| | | | - Mert Döşkaya
- Department of Parasitology, Faculty of Medicine, Ege University, Bornova, İzmir, Turkey
| |
Collapse
|
21
|
Desoubeaux G, Le-Bert C, Fravel V, Clauss T, Delaune AJ, Soto J, Jensen ED, Flower JE, Wells R, Bossart GD, Cray C. Evaluation of a genus-specific ELISA and a commercial Aspergillus Western blot IgG® immunoblot kit for the diagnosis of aspergillosis in common bottlenose dolphins (Tursiops truncatus). Med Mycol 2018; 56:847-856. [PMID: 29228323 DOI: 10.1093/mmy/myx114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 10/10/2017] [Indexed: 01/20/2023] Open
Abstract
Aspergillosis is a fungal infection with high mortality and morbidity rates. As in humans, its definitive diagnosis is difficult in animals, and thus new laboratory tools are required to overcome the diagnostic limitations due to low specificity and lack of standardization. In this study of common bottlenose dolphins (Tursiops truncatus), we evaluated the diagnostic performance of a new commercial immunoblot kit that had been initially developed for the serologic diagnosis of chronic aspergillosis in humans. Using this in a quantitative approach, we first established its positive cutoff within an observation cohort of 32 serum samples from dolphins with "proven" or "probable" diagnosis of aspergillosis and 55 negative controls. A novel enzyme-linked immunosorbent assay (ELISA) test was also developed for detecting anti-Aspergillus antibodies, and results were compared between the two assays. Overall, the diagnostic performance of immunoblot and ELISA were strongly correlated (P < .0001). The former showed lower sensitivity (65.6% versus 90.6%), but higher specificity (92.7% vs. 69.1%), with no cross-reaction with other fungal infections caused by miscellaneous non-Aspergillus genera. When assessing their use in a validation cohort, the immunoblot kit and the ELISA enabled positive diagnosis before mycological cultures in 42.9% and 33.3% subjects addressed for suspicion of aspergillosis, respectively. There was also significant impact of antifungal treatment on the results of the two tests (P < .05). In all, these new serological methods show promise in aiding in the diagnosis of aspergillosis in dolphins, and illustrate the opportunity to adapt commercial reagents directed for human diagnostics to detect similar changes in other animals.
Collapse
Affiliation(s)
- Guillaume Desoubeaux
- University of Miami, Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, Miami, FL - USA.,CHU de Tours, Service de Parasitologie - Mycologie - Médecine tropicale, Tours - France.,Université François-Rabelais, CEPR - INSERM U1100 / Équipe 3, Faculté de Médecine, Tours - France
| | | | | | | | | | - Jeny Soto
- University of Miami, Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, Miami, FL - USA
| | - Eric D Jensen
- U.S. Navy Marine Mammal Program, San Diego, CA - USA
| | - Jennifer E Flower
- Mystic Aquarium, a division of Sea Research Foundation Inc., Mystic, CT - USA
| | - Randall Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, Sarasota, FL - USA
| | - Gregory D Bossart
- University of Miami, Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, Miami, FL - USA.,Georgia Aquarium, Atlanta, GA - USA
| | - Carolyn Cray
- University of Miami, Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, Miami, FL - USA
| |
Collapse
|
22
|
Evaluation of a New Immunochromatography Technology Test (LDBio Diagnostics) To Detect Toxoplasma IgG and IgM: Comparison with the Routine Architect Technique. J Clin Microbiol 2017; 55:3395-3404. [PMID: 28954897 DOI: 10.1128/jcm.01106-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/08/2017] [Indexed: 11/20/2022] Open
Abstract
A study comparing the ICT (immunochromatography technology) Toxoplasma IgG and IgM rapid diagnostic test (LDBio Diagnostics, France) with a fully automated system, Architect, was performed on samples from university hospitals of Marseille and Saint-Etienne. A total of 767 prospective sera and 235 selected sera were collected. The panels were selected to test various IgG and IgM parameters. The reference technique, Toxoplasma IgGII Western blot analysis (LDBio Diagnostics), was used to confirm the IgG results, and commercial kits Platelia Toxo IgM (Bio-Rad) and Toxo-ISAgA (bioMérieux) were used in Saint-Etienne and Marseille, respectively, as the IgM reference techniques. Sensitivity and specificity of the ICT and the Architect IgG assays were compared using a prospective panel. Sensitivity was 100% for the ICT test and 92.1% for Architect (cutoff at 1.6 IU/ml). The low-IgG-titer serum results confirmed that ICT sensitivity was superior to that of Architect. Specificity was 98.7% (ICT) and 99.8% (Architect IgG). The ICT test is also useful for detecting IgM without IgG and is both sensitive (100%) and specific (100%), as it can distinguish nonspecific IgM from specific Toxoplasma IgM. In comparison, IgM sensitivity and specificity on Architect are 96.1% and 99.6%, respectively (cutoff at 0.5 arbitrary units [AU]/ml). To conclude, this new test overcomes the limitations of automated screening techniques, which are not sensitive enough for IgG and lack specificity for IgM (rare IgM false-positive cases).
Collapse
|
23
|
Armengol C, Cassaing S, Roques-Malecaze C, Chauvin P, Iriart X, Berry A, Fillaux J. Time before anti-Toxoplasma IgG seroconversion detection by 7 commercial assays in French pregnant women. Diagn Microbiol Infect Dis 2016; 87:103-107. [PMID: 27884549 DOI: 10.1016/j.diagmicrobio.2016.10.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/18/2016] [Accepted: 10/19/2016] [Indexed: 11/28/2022]
Abstract
We assessed the ability to early detect a toxoplasmic seroconversion between 1 immunoblot (LDBIO II®) and 6 automated assays (TGS TA®, Architect®, Vidas II®, Liaison II®, Platelia®, and Elecsys®), comparing the time before anti-Toxoplasma gondii IgG detection during infection in pregnant women. From 2007 to 2015, 620 sera of 269 women were included. The median durations before positive IgG detection with Vidas II®, Liaison II®, Platelia®, and Elecsys® were significantly longer than Architect® with differential times from 11 to 28days (P<0.001). This time was significantly shortened by the use of LDBIO®, resulting in a saving of 13days (P<0.001). The detection of a positive rate of IgG with TGS TA® was as early as Architect® (P=0.105). The ability to early detect a toxoplasmic seroconversion is not equivalent between the assays and has to be considered when selecting the reagents to reduce the time to therapeutic intervention.
Collapse
Affiliation(s)
- Catherine Armengol
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France
| | - Sophie Cassaing
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France; Pharmacochimie et Biologie Pour le Développement (PHARMA-DEV), IRD UMR 152 Université Paul Sabatier, Toulouse, 31400, France
| | | | - Pamela Chauvin
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France
| | - Xavier Iriart
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France
| | - Antoine Berry
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France
| | - Judith Fillaux
- Service de Parasitologie-Mycologie, Hôpital Purpan, Toulouse, 31059, France; Pharmacochimie et Biologie Pour le Développement (PHARMA-DEV), IRD UMR 152 Université Paul Sabatier, Toulouse, 31400, France.
| |
Collapse
|
24
|
Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis. J Clin Microbiol 2016; 54:3034-3042. [PMID: 27733631 DOI: 10.1128/jcm.01193-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/28/2016] [Indexed: 11/20/2022] Open
Abstract
Toxoplasmosis, a benign infection, is asymptomatic or paucisymptomatic in over 80% of cases, except in immunocompetent patients suffering from ocular toxoplasmosis or in immunocompromised patients with opportunistic or congenital toxoplasmosis. Diagnosis is based mainly on serology testing. Thus, we compared the performance of the nine most commonly used commercial automated or semiautomated immunoassays for IgG and IgM Toxoplasma gondii antibody detection, that is, the Advia Centaur, Architect, AxSYM, Elecsys, Enzygnost, Liaison, Platelia, VIDAS, and VIDIA assays. The assays were conducted on four panels of serum samples derived during routine testing from patients with an interfering disease and who exhibited a low IgG antibody level in one of two clinical settings, namely, acute or chronic toxoplasmosis. As a result, IgG sensitivities ranged from 97.1% to 100%, and IgG specificities ranged from 99.5% to 100%. For IgG quantification, strong differences in IgG titers (expressed in IU/ml) were noted depending on the assay used. IgM sensitivities ranged from 65% to 97.9%, and IgM specificities ranged from 92.6% to 100%. For defining the best serological strategies to be implemented, it appears crucial to compare the diagnostic performance of the different tests with respect to their specificity and sensitivity in detecting the presence of IgG and IgM antibodies.
Collapse
|
25
|
Teh AY, Amerizadeh A, Osman S, Yunus MH, Noordin R. Identification, production and assessment of two Toxoplasma gondii recombinant proteins for use in a Toxoplasma IgG avidity assay. Pathog Glob Health 2016; 110:277-286. [PMID: 27697019 DOI: 10.1080/20477724.2016.1238186] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The IgG avidity assay is an important tool in the management of suspected toxoplasmosis in pregnant women. This study aimed to produce new Toxoplasma gondii recombinant proteins and to assess their usefulness in an IgG avidity assay. Toxoplasma positive and negative serum samples were used, the former were categorized into low (LGA) and high (HGA) IgG avidity samples. Immunoblots were performed on 30 T. gondii cDNA clones to determine the reactivity and IgG avidity to the expressed proteins. Two of the clones were found to have diagnostic potential and were analyzed further; AG12b encoded T. gondii apical complex lysine methyltransferase (AKMT) protein and AG18 encoded T. gondii forkhead-associated (FHA) domain-containing protein. The His-tagged recombinant proteins, rAG12b and rAG18, were expressed and tested with LGA and HGA samples using an IgG avidity western blot and ELISA. With the IgG avidity western blot, rAG12b identified 86.4% of LGA and 90.9% of HGA samples, whereas rAG18 identified 81.8% of both LGA and HGA samples. With the IgG avidity ELISA, rAG12b identified 86.4% of both LGA and HGA samples, whereas rAG18 identified 77.3% of LGA and 86.4% of HGA serum samples. This study showed that the recombinant antigens were able to differentiate low avidity and high avidity serum samples, suggesting that they are potential candidates for use in the Toxoplasma IgG avidity assay.
Collapse
Affiliation(s)
- Ai Ying Teh
- a Institute for Research in Molecular Medicine , Universiti Sains Malaysia , Penang , Malaysia
| | - Atefeh Amerizadeh
- a Institute for Research in Molecular Medicine , Universiti Sains Malaysia , Penang , Malaysia
| | - Sabariah Osman
- a Institute for Research in Molecular Medicine , Universiti Sains Malaysia , Penang , Malaysia
| | - Muhammad Hafiznur Yunus
- a Institute for Research in Molecular Medicine , Universiti Sains Malaysia , Penang , Malaysia
| | - Rahmah Noordin
- a Institute for Research in Molecular Medicine , Universiti Sains Malaysia , Penang , Malaysia
| |
Collapse
|
26
|
Zhang K, Lin G, Han Y, Li J. Serological diagnosis of toxoplasmosis and standardization. Clin Chim Acta 2016; 461:83-9. [DOI: 10.1016/j.cca.2016.07.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/19/2016] [Accepted: 07/23/2016] [Indexed: 11/26/2022]
|
27
|
Villard O, Cimon B, L'Ollivier C, Fricker-Hidalgo H, Godineau N, Houze S, Paris L, Pelloux H, Villena I, Candolfi E. Serological diagnosis of Toxoplasma gondii infection: Recommendations from the French National Reference Center for Toxoplasmosis. Diagn Microbiol Infect Dis 2015; 84:22-33. [PMID: 26458281 DOI: 10.1016/j.diagmicrobio.2015.09.009] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 09/03/2015] [Accepted: 09/09/2015] [Indexed: 11/17/2022]
Abstract
Toxoplasmosis manifests no clinical signs in 80% of cases in immunocompetent patient, causing immunization characterized by the persistence of cysts, particularly in brain, muscles, and retina. Assessing the serological status, based on testing for serum toxoplasma IgG and IgM antibodies, is essential in cases that are increasingly at risk for the more severe disease forms, such as congenital or ocular toxoplasmosis. This disease also exposes immunosuppressed patients to reactivation, which can lead to more widespread forms and increased mortality. By interpreting the serological results, we can estimate the risk of contamination or reactivation and define appropriate prophylactic and preventive measures, such as hygienic and dietetic, therapeutic, biological, and clinical follow-up, according to the clinical context. We hereby propose practical approaches based on serological data, resulting from a consensus of a group of experts from the French National Reference Center Network for Toxoplasmosis, according to both routine and specific clinical situations.
Collapse
Affiliation(s)
- O Villard
- Institut de Parasitologie et de Pathologie Tropicale de Strasbourg, Université de Strasbourg, Hôpitaux Universitaires de Strasbourg, 1-3 rue Koeberlé, F-67000 Strasbourg, France.
| | - B Cimon
- Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire, 4 rue Larrey, F-49933 Angers Cedex 9, France
| | - C L'Ollivier
- Laboratoire de Parasitologie-Mycologie, Hôpital de la Timone, 264 rue Saint Pierre, F-13385 Marseille Cedex 05, France
| | - H Fricker-Hidalgo
- Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire A. Michallon et Université de Grenoble BP 217, 38043 Grenoble Cedex, France
| | - N Godineau
- Laboratoire de Parasitologie-Mycologie, Centre Hospitalier de Saint-Denis, 2 rue du Docteur Pierre Delafontaine, BP 279, F-93205 Saint-Denis Cedex, France
| | - S Houze
- Laboratoire de Parasitologie Mycologie, AP-HP Hôpital BICHAT-Claude Bernard, 46 rue Henri Huchard, F-75877 Paris Cedex 18, France
| | - L Paris
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Laboratoire de Parasitologie-Mycologie, 47-83 Boulevard de l'Hôpital, F-75651 Paris Cedex 13, France
| | - H Pelloux
- Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire A. Michallon et Université de Grenoble BP 217, 38043 Grenoble Cedex, France
| | - I Villena
- Laboratoire de Parasitologie-Mycologie, Hôpital Maison Blanche, Centre Hospitalier Universitaire et Université de Reims Champagne Ardennes, 45 rue Cognacq-Jay, F-51092 Reims Cedex, France
| | - E Candolfi
- Institut de Parasitologie et de Pathologie Tropicale de Strasbourg, Université de Strasbourg, Hôpitaux Universitaires de Strasbourg, 1-3 rue Koeberlé, F-67000 Strasbourg, France.
| |
Collapse
|
28
|
Mouri O, Kendjo E, Touafek F, Fekkar A, Konte O, Imbert S, Courtin R, Mazier D, Paris L. The impact of lowering the cut-off value on the sensitivity of the Platelia Elisa IgG (Bio-Rad) test for toxoplasmosis diagnosis. ACTA ACUST UNITED AC 2015; 22:22. [PMID: 26187780 PMCID: PMC4506486 DOI: 10.1051/parasite/2015022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 06/29/2015] [Indexed: 11/17/2022]
Abstract
Determining specific immune status against Toxoplasma gondii is essential for assessing the risk of reactivation in immunocompromised patients or defining serological monitoring and appropriate prophylactic measures during pregnancy. In France, toxoplasmosis serological screening requires systematic testing for IgM and IgG antibodies. The Platelia Toxo IgG and IgM test (Bio-Rad) is one of the most widely used tests for anti-toxoplasmic antibody detection. We performed a study on 384 sera, including 123 IgG negative (<6 IU/mL) and 261 IgG equivocal (6–9 IU/mL) sera tested with Platelia Toxo IgG and collected during routine screening at Pitié-Salpêtrière Hospital, Paris, France to determine the best-performing IgG titer cut-off value. Out of these 383 sera, 298 were IgM negative by Platelia Toxo IgM and 86 were IgM positive. All sera were also tested against Toxo IgG II LD BIO western blot test as confirmation. Our results indicated that an IgG titer cut-off value of ≥4.4 IU/mL for the Platelia Toxo IgG met the definition of positivity, a value significantly lower than that indicated by the manufacturers. In the presence of IgM antibodies, the IgG titer cut-off decreased significantly to a value ≥0.2 IU/mL. This latter cut-off also allowed adequate diagnosis of proven toxoplasmosis seroconversion in 76.7% of cases (33/43). Our findings may improve toxoplasmosis care by reducing therapeutic intervention time and eliminating the need for further serological monitoring.
Collapse
Affiliation(s)
- Oussama Mouri
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Eric Kendjo
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Feriel Touafek
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Arnaud Fekkar
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France - Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, 75013 Paris, France - Sorbonne Universités, UPMC Université Paris 6, CIMI-Paris, 75005 Paris, France
| | - Ousmane Konte
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Sebastien Imbert
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Régis Courtin
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| | - Dominique Mazier
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France - Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, 75013 Paris, France - Sorbonne Universités, UPMC Université Paris 6, CIMI-Paris, 75005 Paris, France
| | - Luc Paris
- AP-HP, Groupe Hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, 75013 Paris, France
| |
Collapse
|
29
|
Evaluation of the Aspergillus Western blot IgG kit for diagnosis of chronic aspergillosis. J Clin Microbiol 2014; 53:248-54. [PMID: 25392351 DOI: 10.1128/jcm.02690-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Immunoprecipitin detection (IPD) is the current reference confirmatory technique for anti-Aspergillus antibody detection; however, the lack of standardization is a critical drawback of this assay. In this study, we evaluated the performance of the Aspergillus Western blot (Asp-WB) IgG kit (LDBio Diagnostics, Lyon, France), a recently commercialized immunoblot assay for the diagnosis of various clinical presentations of chronic aspergillosis. Three hundred eight serum samples from 158 patients with aspergillosis sensu lato (s.l.) were analyzed. More specifically, 267 serum samples were derived from patients with Aspergillus disease, including 89 cases of chronic pulmonary aspergillosis, 10 of aspergilloma, and 32 of allergic bronchopulmonary aspergillosis, while 41 samples were from patients with Aspergillus colonization, including 15 cystic fibrosis (CF) and 12 non-CF patients. For blood donor controls, the Asp-WB specificity was 94%, while the kit displayed a sensitivity for the aspergillosis s.l. diagnosis of 88.6%, with a diagnostic odds ratio (DOR) of 119 (95% confidence interval [CI], 57 to 251). The DOR values were 185.22 (95% CI,78.79 to 435.45) and 43.74 (95% CI, 15.65 to 122.20) for the diagnosis of Aspergillus disease and Aspergillus colonization, respectively. Among the patients, the sensitivities of the Asp-WB in the diagnosis of Aspergillus colonization were 100% and 41.7% in CF and non-CF patients, respectively. The Asp-WB yielded fewer false-negative results than did IPD. In conclusion, the Asp-WB kit performed well for the diagnosis of various clinical presentations of aspergillosis in nonimmunocompromised patients, with an enhanced standardization and a higher sensitivity than with IPD, which is the current reference method.
Collapse
|
30
|
Khammari I, Saghrouni F, Lakhal S, Bougmiza I, Bouratbine A, Ben Said M, Boukadida J. Identification of soluble and membrane antigenic markers of acquired toxoplasmosis by immunoblot. Parasite Immunol 2014; 36:684-93. [PMID: 25384440 DOI: 10.1111/pim.12139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 08/13/2014] [Indexed: 11/29/2022]
Abstract
The overall performance of quantitative assays in the detection of anti-Toxoplasma IgG is satisfactory, but discrepancies between assays are not uncommon especially when IgG concentrations are close to the limit of detection of the tests. The purpose of our study was to identify soluble and membrane antigens extracted from Toxoplasma gondii tachyzoites by immunoblot to select the most relevant antigenic bands to be used for qualitative serodiagnosis of acquired toxoplasmosis. We selected five relevant bands (98, 36, 33, 32 and 21 kDa) with soluble antigens and four relevant bands (42, 35, 32 and 30 kDa) with membrane antigens which gave high sensitivity and/or specificity in immunodiagnosis. The association on the same blot of at least three of the five relevant bands in the soluble antigen immunoblot showed the highest sensitivity/specificity (97.4%/99.0%, respectively). Our results indicate that immunoblot using soluble tachyzoite extract with simultaneous detection of at least three of the five bands (98, 36, 33, 32 and 21 kDa) represents a valuable test for serodiagnosis of acquired toxoplasmosis and should be further evaluated as a confirmatory test for sera which give discrepant results in quantitative assays.
Collapse
Affiliation(s)
- I Khammari
- Research Unit (UR12SP34), Farhat Hached University Hospital, Sousse, Tunisia
| | | | | | | | | | | | | |
Collapse
|
31
|
Khammari I, Saghrouni F, Lakhal S, Bouratbine A, Ben Said M, Boukadida J. A new IgG immunoblot kit for diagnosis of toxoplasmosis in pregnant women. THE KOREAN JOURNAL OF PARASITOLOGY 2014; 52:493-9. [PMID: 25352697 PMCID: PMC4210731 DOI: 10.3347/kjp.2014.52.5.493] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/12/2014] [Accepted: 06/15/2014] [Indexed: 11/23/2022]
Abstract
The determination of the accurate immune status of pregnant women is crucial in order to prevent congenital toxoplasmosis. Equivocal results with conventional serological techniques are not uncommon when IgG titers are close to the cut-off value of the test, so that a confirmatory technique is needed. For this purpose, we developed a homemade immunoblot (IB) using soluble extract of Toxoplasma gondii tachyzoites and assessed it by testing 154 positive, 100 negative, and 123 equivocal sera obtained from pregnant women. In order to select the more valuable bands in terms of sensitivity and specificity, we used the Youden Index (YI). The highest YIs were those given by the 32, 36, 98, 21, and 33 bands. The simultaneous presence on the same blot of at least 3 bands showed a much higher YI (0.964) and was adapted as the positivity criterion. The analysis of results showed that our homemade IB correlated well with the commercial LDBIO Toxo II IgG® kit recently recommended as a confirmatory test (96.7% of concordance).
Collapse
Affiliation(s)
- Imen Khammari
- Research Unit, UR12SP34, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse 4000, Tunisia
| | - Fatma Saghrouni
- Research Unit, UR12SP34, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse 4000, Tunisia
| | - Sami Lakhal
- Research Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR 11 IPT06 Pasteur Institute of Tunis, 13 Place Pasteur, B.P. 74, 1002 Tunis, Belvédère, Tunisia
| | - Aida Bouratbine
- Research Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR 11 IPT06 Pasteur Institute of Tunis, 13 Place Pasteur, B.P. 74, 1002 Tunis, Belvédère, Tunisia
| | - Moncef Ben Said
- Research Unit, UR12SP34, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse 4000, Tunisia
| | - Jalel Boukadida
- Research Unit, UR12SP34, Farhat Hached University Hospital, Ibn Jazzar Street, Sousse 4000, Tunisia
| |
Collapse
|
32
|
Performance of the BioPlex 2200 flow immunoassay in critical cases of serodiagnosis of toxoplasmosis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:496-500. [PMID: 24477853 DOI: 10.1128/cvi.00624-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The BioPlex 2200 automated analyzer (Bio-Rad Laboratories, Hercules, CA) is a recently developed multiplex analyzer that enables the detection of anti-Toxoplasma, -rubella, and -cytomegalovirus antibodies in the same assay. The aim of this study was to compare this new technology (using the BioPlex 2200 ToRC IgG/IgM kit) in critical cases of serodiagnosis of toxoplasmosis (acute, chronic, or congenital infections and cases with discrepant results) to the technologies used in our routine practice, i.e., the Platelia IgG/IgM enzyme-linked immunosorbent assays (ELISAs) (Bio-Rad Laboratories) and the Toxo-Screen direct agglutination assay (bioMérieux, Lyon, France). Overall, most cases of false-positive/negative results obtained with the Platelia IgG or Toxo-Screen assay were corrected by the BioPlex 2200 ToRC IgG (87.5%). Furthermore, the analysis of 35 sequences of sera showed a trend toward a more rapid decrease of IgM titers by BioPlex 2200 than by Platelia. These results for IgM detection can be explained by a weaker detection of residual IgM. Indeed, among 23 serum samples from patients with probable past infection with long-lasting IgM (Platelia M positive and IgG avidity index, ≥0.5), the BioPlex 2200 Toxoplasma IgM assay was positive for only 11 serum samples. In our panel of critical cases comprising 156 serum and 6 cord blood samples from 103 patients with acute, chronic, or congenital infection, the BioPlex 2200 IgG assay was a sensitive (97.8%) and specific (91.3%) method for IgG detection. The high specificity (97.4%) of IgM detection combined with the shorter kinetics of IgM titers may considerably reduce the number of residual IgM detections, thus yielding more precise diagnoses of acute infections.
Collapse
|
33
|
Murat JB, Fricker Hidalgo H, Brenier-Pinchart MP, Pelloux H. Human toxoplasmosis: which biological diagnostic tests are best suited to which clinical situations? Expert Rev Anti Infect Ther 2014; 11:943-56. [DOI: 10.1586/14787210.2013.825441] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
34
|
Khammari I, Saghrouni F, Yaacoub A, Gaied Meksi S, Ach H, Garma L, Fathallah A, Ben Saïd M. IgG western blot for confirmatory diagnosis of equivocal cases of toxoplasmosis by EIA-IgG and fluorescent antibody test. THE KOREAN JOURNAL OF PARASITOLOGY 2013; 51:485-8. [PMID: 24039295 PMCID: PMC3770883 DOI: 10.3347/kjp.2013.51.4.485] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/19/2013] [Accepted: 07/05/2013] [Indexed: 11/23/2022]
Abstract
The performance values of available techniques used in serodiagnosis of toxoplasmosis are satisfactory but they raise problems of equivocal and discordant results for very low IgG titers. Recently marketed, LDBio-Toxo II IgG Western blot (IB) showed an excellent correlation with the dye test. We estimated the proportion of equivocal and discordant results between the enzyme immunoassay Platelia Toxo IgG (EIA-IgG) and fluorescent antibody test (FAT) and assessed the usefulness of the IB as a confirmatory test. Out of 2,136 sera collected from pregnant women, 1,644 (77.0%) tested unequivocally positive and 407 (19.0%) were negative in both EIA-IgG and FAT. The remaining 85 (4%) sera showed equivocal or discordant results. Among them, 73 (85.9%) were positive and 12 (14.1%) were negative in IB. Forty-one (89.1%) equivocal sera in EIA-IgG and 46 (86.8%) equivocal sera in FAT were positive in IB. Reducing the cut-off values of both screening techniques improved significantly their sensitivity in detecting very low IgG titers at the expense of their specificity. In conclusion, equivocal results in routine-used techniques and their discordance in determination of the immune status in pregnancy women were not uncommon. IB test appeard to be highly useful in these situations as a confirmatory technique.
Collapse
Affiliation(s)
- Imen Khammari
- UR 12 SP 34 Research Unit, Ministry of Public Health, Tunis, Tunisia
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Luo Y, Liu X, Jiang T, Liao P, Fu W. Dual-aptamer-based biosensing of toxoplasma antibody. Anal Chem 2013; 85:8354-60. [PMID: 23899133 DOI: 10.1021/ac401755s] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A panel of seven aptamers to antitoxoplasma IgG is first discovered in this report. The aptamers are selected using systematic evolution of ligands by exponential enrichment (SELEX) technology, cloned, and identified by sequencing and affinity assay. Among them, two aptamers (TGA6 and TGA7) with the highest affinities are employed as capture probe and detection probe in developing a quantum dots-labeled dual aptasensor (Q-DAS). In the presence of antitoxoplasma IgG, an aptamer-protein-aptamer sandwich complex (TGA6-IgG-TGA7) is formed and captured on a multiwell microplate, whose fluorescence can be read out using quantum dots as the fluorescence label, ensuring highly sensitive and specific sensing of antitoxoplasma IgG. The operating characteristics of the proposed assay are guaranteed using dual aptamers as the recognizing probes when compared with antibody-based immunoassay. Q-DAS has a linearity within the range of 0.5-500 IU with a lowest detection of 0.1 IU. Receiver operating curves of 212 clinical samples show a 94.8% sensitivity and 95.7% specificity when the cutoff value is set as 6.5 IU, indicating the proposed Q-DAS is a promising assay in large-scale screening of toxoplasmosis.
Collapse
Affiliation(s)
- Yang Luo
- Department of Laboratory Medicine, Southwest Hospital, the Third Military Medical University, Chong Qing 400038, China
| | | | | | | | | |
Collapse
|
36
|
Toxoplasma seroconversion with negative or transient immunoglobulin M in pregnant women: myth or reality? A French multicenter retrospective study. J Clin Microbiol 2013; 51:2103-11. [PMID: 23616461 DOI: 10.1128/jcm.00169-13] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Classically, Toxoplasma infection is associated with high levels of specific IgM antibody and a rise in specific IgG levels 1 to 3 weeks later. Atypical IgG seroconversion, without IgM detection or with transient IgM levels, has been described during serologic follow-up of seronegative pregnant women and raises difficulties in interpreting the results. To evaluate the frequency and the characteristics of these atypical cases of seroconversion, an investigation was conducted within the French National Reference Center for Toxoplasmosis, from which 26 cases collected from 12 laboratories belonging to the network were identified. The aim of this work was to retrospectively analyze the results of serologic testing, the treatments administered, and the results of prenatal and postnatal follow-up for these women. In each case, IgG antibodies were detected using both screening and confirmatory tests. IgM antibodies were not detected in 15 cases, and the levels were equivocal or low-positive in 11 cases. The IgG avidity results were low in 16 cases and high in one case. Most of the pregnant women (22/26) were treated with spiramycin from the time that IgG antibodies appeared until delivery. Amniotic fluid was analyzed for Toxoplasma gondii DNA by PCR in 11/26 cases, and the results were negative in all cases. Congenital toxoplasmosis was ruled out in 12/26 newborns. There was no abnormality observed at birth for 10 newborns and no information available for 4 newborns. In conclusion, when the interpretation of serological results is so difficult, it seems cautious to initiate treatment by spiramycin and to follow the pregnant women and their newborns.
Collapse
|
37
|
Souza GFD, Carvalho D, Pedrosa W, Franck J, Piarroux R. Analytical validation of anti-toxoplasma IgG immunoassays. Braz J Infect Dis 2012; 16:574-6. [DOI: 10.1016/j.bjid.2012.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 07/11/2012] [Indexed: 11/24/2022] Open
|
38
|
Evaluation of the liaison automated testing system for diagnosis of congenital toxoplasmosis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:1859-63. [PMID: 23015644 DOI: 10.1128/cvi.00489-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Congenital toxoplasmosis is a worldwide health problem, and different screening strategies exist. Testing of toxoplasma-specific antibodies in infants identifies congenital toxoplasmosis during the first year of life. However, experience with commercial available immunoassays is limited. The aim of this study was to evaluate both the performance and analytical characteristics of the Liaison diagnostic system in infants. In a retrospective study, serum Toxoplasma gondii antibodies were measured in samples from 333 infants, including 212 noninfected infants and 121 infants with congenital toxoplasmosis. A total of 1,157 umbilical cord blood and peripheral serum samples were analyzed. Liaison toxoplasma-specific IgG and IgM antibodies and the IgG avidity index were compared to the infection status of the infant, determined by the Sabin-Feldman dye test and immunosorbent agglutination assay--IgM. All noninfected infants were seronegative by Liaison IgG within the first year of life. The Liaison system showed a sensitivity of 81.8%, a specificity of 100.0%, a positive predictive value of 100.0%, a negative predictive value of 90.6%, and overall agreement of 84.4% by comparison with the dye test. Overall agreement of both IgM test systems was 96.0%. In this study cohort, avidity did not show a potential diagnostic benefit for the detection of congenital infection. In conclusion, the Liaison system is a valuable tool to monitor the serologic course of infants at risk. A final serologic confirmatory test is recommended to improve the rate of detection of congenital toxoplasmosis at 1 year of life. Protocols of routine follow-up testing in infants and accurate diagnostic tools after acute gestational infections are needed to improve medical care.
Collapse
|
39
|
Abstract
Toxoplasmosis is a worldwide infection caused by the intracellular parasite Toxoplasma gondii. At least a third of the world human population are infected with the parasite, making it one of the most successful parasitic infections. Primary maternal infection may cause health-threatening sequelae for the foetus, or even cause death in uterus. Reactivation of a latent infection in immune deficiency conditions such as AIDS and organ transplantation can cause fatal toxoplasmic encephalitis. Toxoplasmosis is a major cause of retinochoroiditis, especially in individuals with an impaired immune system. Despite the usually 'asymptomatic' nature of the infection, a significant burden imposed by the parasite necessitates the implementation of effective means for the prevention, diagnosis, and management of this disease. Laboratory diagnosis, i.e. PCR and serologic assays, plays the main role in the diagnosis of congenital infection and assists in the confirmatory diagnosis of toxoplasmic encephalitis and ocular toxoplasmosis. Here, we briefly review general aspects of Toxoplasma infection and focus on the diagnostic methods currently used in medical laboratories for the diagnosis of Toxoplasma infection.
Collapse
Affiliation(s)
- Geita Saadatnia
- Molecular Parasitology Laboratory, Parasitology Department, Pasteur Institute of Iran, Tehran, Iran
| | | |
Collapse
|
40
|
Villard O, Cimon B, Franck J, Fricker-Hidalgo H, Godineau N, Houze S, Paris L, Pelloux H, Villena I, Candolfi E. Evaluation of the usefulness of six commercial agglutination assays for serologic diagnosis of toxoplasmosis. Diagn Microbiol Infect Dis 2012; 73:231-5. [DOI: 10.1016/j.diagmicrobio.2012.03.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 03/16/2012] [Accepted: 03/16/2012] [Indexed: 10/28/2022]
|
41
|
Robert-Gangneux F, Dardé ML. Epidemiology of and diagnostic strategies for toxoplasmosis. Clin Microbiol Rev 2012; 25:264-96. [PMID: 22491772 PMCID: PMC3346298 DOI: 10.1128/cmr.05013-11] [Citation(s) in RCA: 997] [Impact Index Per Article: 83.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The apicomplexan parasite Toxoplasma gondii was discovered a little over 100 years ago, but knowledge of its biological life cycle and its medical importance has grown in the last 40 years. This obligate intracellular parasite was identified early as a pathogen responsible for congenital infection, but its clinical expression and the importance of reactivations of infections in immunocompromised patients were recognized later, in the era of organ transplantation and HIV infection. Recent knowledge of host cell-parasite interactions and of parasite virulence has brought new insights into the comprehension of the pathophysiology of infection. In this review, we focus on epidemiological and diagnostic aspects, putting them in perspective with current knowledge of parasite genotypes. In particular, we provide critical information on diagnostic methods according to the patient's background and discuss the implementation of screening tools for congenital toxoplasmosis according to health policies.
Collapse
Affiliation(s)
- Florence Robert-Gangneux
- Service de Parasitologie, Faculté de Médecine et Centre Hospitalier Universitaire de Rennes, Rennes, France.
| | | |
Collapse
|
42
|
Khammari I, Saghrouni F, Bougmiza I, Gheith S, Ben Abdejlil J, Yaacoub A, Boukadida J, Babba H, Ben Saïd M. [Evaluation of the immunoblotting for the detection of immunoglobulin G Toxoplasma antibodies in immunocompetent patients]. ACTA ACUST UNITED AC 2011; 60:160-5. [PMID: 22079082 DOI: 10.1016/j.patbio.2011.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 02/10/2011] [Indexed: 11/30/2022]
Abstract
UNLABELLED The serological tests commonly used for the diagnosis of toxoplasmosis raise the problem of the interpretation of the borderline immunoglobulin G (IgG) levels and discordant results between various tests. OBJECTIVE The purpose of our study was to evaluate the contribution of the immunoblotting in the detection of specific IgG in acquired toxoplasmosis of immunocompetent patients especially when levels are equivocal or discordant in enzyme-linked immunosorbent assay (Elisa) and indirect fluorescent antigen test (IFAT). MATERIAL AND METHODS [corrected] We tested three groups of sera. The first included 87 positive sera, the second 33 negative sera, and the last one 29 equivocal sera. RESULTS Results obtained with the first and the second group of sera led us to identify the bands 30kDa and 32kDa as markers of the toxoplasmic infection. The simultaneous presence of both bands showed a sensitivity of 91.5%, a specificity of 96.9%, a VPP of 98.7%, a VPN of 74.4% and a Youden's index of 0.88. Our findings suggest that the presence of these two bands is a reliable criterion for the confirmation of the presence of anti-toxoplasmic IgG in the corresponding serum. The immunoblot allowed us to ascertain serological status of 27 (93.1%) patients from the third group in which results were discrepant or equivocal in Elisa and/or in IFAT. CONCLUSION Immunoblot is a useful serological test for detection of very low or equivocal titers.
Collapse
Affiliation(s)
- I Khammari
- Laboratoire de parasitologie-mycologie, CHU Farhat Hached, rue Mohamed Karoui, 4000 Sousse, Tunisie.
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Utility of immunoblotting for early diagnosis of toxoplasmosis seroconversion in pregnant women. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:1908-12. [PMID: 21880851 DOI: 10.1128/cvi.05303-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Congenital transmission of Toxoplasma gondii occurs mainly when a mother acquires the infection for the first time during pregnancy. It was recently shown that although early treatment of the primary infection during pregnancy has little or no impact on the fetomaternal transmission rate, it does reduce the incidence of sequelae in infected infants. Seroconversion is defined by the appearance of IgG. Commercial reagents continue to vary considerably in detecting low concentrations of antibodies, as during early seroconversion. We compared two routinely used immunoassays (IA) (Platelia and Elecsys Toxo IgG) and an indirect immunofluorescence assay (IIF) with a qualitative test based on immunoblot analysis (Toxo II IgG) (IB) to assess their abilities to diagnose seroconversion at its earliest stages. This prospective study was carried out between January and November 2010. It included 39 pregnant women with monthly follow-up who seroconverted during pregnancy. On first sera that were IgM positive but IgG negative (or equivocal) as detected by IA, IB diagnosed seroconversion twice as often as IIF (26/39 [66.7%] versus 13/39 [33.3%]; P < 0.001; χ(2) test). Serum samples were retaken 2 to 5 weeks later for the other 13 cases (IgG negative by IB on first serum). Seroconversion was demonstrated as follows: IB for 5 cases where IA remained negative or equivocal, IB and IIF for 5 cases where IA remained negative or equivocal, IA for 2 cases, and no method for 1 case (a third sample was necessary). In summary, IB permitted toxoplasmosis seroconversion diagnosis before other means in 92.3% of cases (36/39) and thus earlier therapeutic intervention.
Collapse
|
44
|
Değirmenci A, Döşkaya M, Caner A, Çiçek C, Korkmaz M, Gürüz Y, Üner A. Toxoplasma gondii RH Ankara: Production of evolving tachyzoites using a novel cell culture method. Exp Parasitol 2011; 128:1-8. [DOI: 10.1016/j.exppara.2011.01.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 01/26/2011] [Accepted: 01/27/2011] [Indexed: 10/18/2022]
|
45
|
Leslé F, Touafek F, Fekkar A, Mazier D, Paris L. Discrepancies between a new highly sensitive Toxoplasma gondii ELISA assay and other reagents: interest of Toxo IgG Western blot. Eur J Clin Microbiol Infect Dis 2011; 30:1207-12. [PMID: 21484254 DOI: 10.1007/s10096-011-1214-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 03/03/2011] [Indexed: 10/17/2022]
Abstract
Immunodiagnostic assays are commonly used to screen for maternal toxoplasmic seroconversion during pregnancy. The introduction to the market of a new highly sensitive IgG assay, the Elecsys Toxo IgG test, has resulted in discrepancy issues with other immunoassays because of a lack of standardisation. Western blot appears to be a good alternative gold standard to the dye test, as the latter is not routinely available. For the present prospective study, we compared the analytical performances of two immunoassays, Elecsys Toxo IgG (Roche Diagnostics) and Platelia Toxo IgG (Bio-Rad, Marnes la Coquette, France), to Toxo II IgG Western blot (LDBio, Lyon, France) using 231 consecutive sera with low or equivocal IgG titres. Of these 231 sera, 213 presented discrepancies, which showed the importance of a confirmation test. Of the Elecsys Toxo IgG-positive results, 100% were confirmed by the Western blot with a positive threshold of 30 IU/ml for Elecsys; in the equivocal area (1-30 IU/ml), Western blot is negative in 54% of cases. Our results suggest that the lower diagnostic cut-off of Platelia Toxo IgG should be further reduced. Our study indirectly confirms that monitoring, especially for pregnant women, must be done in the same laboratory using the same technique. The ability to diagnose very early seroconversion using Western blot merits further study.
Collapse
Affiliation(s)
- F Leslé
- AP-HP, Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Pitié-Salpétrière, 47 and 83 Boulevard de l'Hôpital, 75013 Paris, France
| | | | | | | | | |
Collapse
|
46
|
Bicentric evaluation of six anti-toxoplasma immunoglobulin G (IgG) automated immunoassays and comparison to the Toxo II IgG Western blot. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:1322-6. [PMID: 19587151 DOI: 10.1128/cvi.00128-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A comparative study of the Toxoplasma IgG(I) and IgG(II) Access (Access I and II, respectively; Beckman Coulter Inc.), AxSYM Toxo IgG (AxSYM; Abbott Diagnostics), Vidas Toxo IgG (Vidas; bioMerieux, Marcy l'Etoile, France), Immulite Toxo IgG (Immulite; Siemens Healthcare Diagnostics Inc.), and Modular Toxo IgG (Modular; Roche Diagnostics, Basel, Switzerland) tests was done with 406 consecutive serum samples. The Toxo II IgG Western blot (LDBio, Lyon, France) was used as a reference technique in the case of intertechnique discordance. Of the 406 serum samples tested, the results for 35 were discordant by the different techniques. Using the 175 serum samples with positive results, we evaluated the standardization of the titrations obtained (in IU/ml); the medians (second quartiles) obtained were 9.1 IU/ml for the AxSYM test, 21 IU/ml for the Access I test, 25.7 IU/ml for the Access II test, 32 IU/ml for the Vidas test, 34.6 IU/ml for the Immulite test, and 248 IU/ml for the Modular test. For all the immunoassays tested, the following relative sensitivity and specificity values were found: 89.7 to 100% for the Access II test, 89.7 to 99.6% for the Immulite test, 90.2 to 99.6% for the AxSYM test, 91.4 to 99.6% for the Vidas test, 94.8 to 99.6% for the Access I test, and 98.3 to 98.7% for the Modular test. Among the 406 serum samples, we did not find any false-positive values by two different tests for the same serum sample. Except for the Modular test, which prioritized sensitivity, it appears that the positive cutoff values suggested by the pharmaceutical companies are very high (either for economical or for safety reasons). This led to imperfect sensitivity, a large number of unnecessary serological follow-ups of pregnant women, and difficulty in determining the serological status of immunosuppressed individuals.
Collapse
|
47
|
|
48
|
|