1
|
Laguardia MC, Carellos EVM, Andrade GMQ, Carneiro M, Januário JN, Vitor RWDA. Evaluation of different cut-off points for IgG avidity and IgM in the diagnosis of acute toxoplasmosis in pregnant women participating in a congenital toxoplasmosis screening program. Rev Inst Med Trop Sao Paulo 2024; 66:e43. [PMID: 39082482 PMCID: PMC11295287 DOI: 10.1590/s1678-9946202466043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 06/10/2024] [Indexed: 08/04/2024] Open
Abstract
The main social impact of toxoplasmosis stems from its ability to be vertically transmitted. Postnatally acquired infection is generally asymptomatic in approximately 70-90% of cases, making diagnosis often dependent on laboratory tests using serological methods to search for anti-T. gondii antibodies. This study aimed to investigate the ability of the VIDAS TOXO IgG avidity and VIDAS TOXO IgM assays to confirm recent toxoplasmosis. In total, 341 pregnant women with suspected acute toxoplasmosis were systematically monitored in the Program for Control of Congenital Toxoplasmosis in Minas Gerais State, Brazil. We conducted an observational analytical-descriptive cross-sectional study and grouped according to clinical and laboratory criteria as having acute or chronic toxoplasmosis. The VIDAS TOXO IgG avidity and VIDAS TOXO IgM assays were evaluated to investigate the capacity to identify acute infection. IgG avidity showed good performance in identifying acute toxoplasmosis when the IgG avidity index was lower than or equal to 0.1. Values greater than or equal to 3.16 according to the TOXO IgM kit were associated with a greater chance of acute infection. These results may contribute to a more adequate diagnosis of acute gestational toxoplasmosis and, consequently, the avoidance of inadequate or unnecessary treatments.
Collapse
Affiliation(s)
- Michelle Costa Laguardia
- Secretaria de Estado de Saúde de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia, Belo Horizonte, Minas Gerais, Brazil
| | - Ericka Viana Machado Carellos
- Universidade Federal de Minas Gerais, Faculdade de Medicina, Departamento de Pediatria, Belo Horizonte, Minas Gerais, Brazil
| | - Glaucia Manzan Queiroz Andrade
- Universidade Federal de Minas Gerais, Faculdade de Medicina, Departamento de Pediatria, Belo Horizonte, Minas Gerais, Brazil
| | - Mariângela Carneiro
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia, Belo Horizonte, Minas Gerais, Brazil
| | - José Nélio Januário
- Universidade Federal de Minas Gerais, Faculdade de Medicina, Núcleo de Ações e Pesquisa em Apoio Diagnóstico, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo Wagner de Almeida Vitor
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia, Belo Horizonte, Minas Gerais, Brazil
| |
Collapse
|
2
|
Li Y, Yang HS, Klasse PJ, Zhao Z. The significance of antigen-antibody-binding avidity in clinical diagnosis. Crit Rev Clin Lab Sci 2024:1-15. [PMID: 39041650 DOI: 10.1080/10408363.2024.2379286] [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: 03/12/2024] [Accepted: 07/09/2024] [Indexed: 07/24/2024]
Abstract
Immunoglobulin G (IgG) and immunoglobulin M (IgM) testing are commonly used to determine infection status. Typically, the detection of IgM indicates an acute or recent infection, while the presence of IgG alone suggests a chronic or past infection. However, relying solely on IgG and IgM antibody positivity may not be sufficient to differentiate acute from chronic infections. This limitation arises from several factors. The prolonged presence of IgM can complicate diagnostic interpretations, and false positive IgM results often arise from antibody cross-reactivity with various antigens. Additionally, IgM may remain undetectable in prematurely collected samples or in individuals who are immunocompromised, further complicating accurate diagnosis. As a result, additional diagnostic tools are required to confirm infection status. Avidity is a measure of the strength of the binding between an antigen and antibody. Avidity-based assays have been developed for various infectious agents, including toxoplasma, cytomegalovirus (CMV), SARS-CoV-2, and avian influenza, and are promising tools in clinical diagnostics. By measuring the strength of antibody binding, they offer critical insights into the maturity of the immune response. These assays are instrumental in distinguishing between acute and chronic or past infections, monitoring disease progression, and guiding treatment decisions. The development of automated platforms has optimized the testing process by enhancing efficiency and minimizing the risk of manual errors. Additionally, the recent advent of real-time biosensor immunoassays, including the label-free immunoassays (LFIA), has further amplified the capabilities of these assays. These advances have expanded the clinical applications of avidity-based assays, making them useful tools for the diagnosis and management of various infectious diseases. This review is structured around several key aspects of IgG avidity in clinical diagnosis, including: (i) a detailed exposition of the IgG affinity maturation process; (ii) a thorough discussion of the IgG avidity assays, including the recently emerged biosensor-based approaches; and (iii) an examination of the applications of IgG avidity in clinical diagnosis. This review is intended to contribute toward the development of enhanced diagnostic tools through critical assessment of the present landscape of avidity-based testing, which allows us to identify the existing knowledge gaps and highlight areas for future investigation.
Collapse
Affiliation(s)
- Yaxin Li
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - He S Yang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - P J Klasse
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Zhen Zhao
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| |
Collapse
|
3
|
Kodym P, Kurzová Z, Berenová D, Malý M. Detection of persistent low IgG avidity-an interpretative problem in the diagnosis of acute toxoplasmosis. PLoS One 2023; 18:e0284499. [PMID: 37053239 PMCID: PMC10101438 DOI: 10.1371/journal.pone.0284499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 04/02/2023] [Indexed: 04/14/2023] Open
Abstract
OBJECTIVES For the proper diagnosis of toxoplasmosis it is essential to determine the stage of the infection, for which the most preferred method is IgG avidity test. The avidity index (AI) should initially be low (AI≤0.3) in the acute phase and increase during the infection. However, persistent low avidity can occur in patients with latent toxoplasmosis, which can complicate the interpretation of the results. The aim of the study is to explain the causes of this phenomenon. METHODOLOGY A retrospective study was carried out with 717 serum samples collected from 442 patients from the categories of pregnant and non-pregnant women, men, and newborns + infants (age < 0.5 year). The trends of AI kinetics were evaluated in repeatedly examined patients. The frequency of cases with low avidity was compared in individual categories of patients and in groups of people with acute and non-acute toxoplasmosis. RESULTS The proportion of patients with initially low avidity was 42.1% in the acute toxoplasmosis group while it was 13.0% in the non-acute groups. In uninfected newborns with anti-Toxoplasma antibodies transmitted from the mother, a decrease in IgG avidity levels over time was observed, resulting in 29.2% of samples showing low (improper) avidity. While the dynamics of IgG avidity and the frequency of cases of improperly low avidity were similar in men and pregnant and non-pregnant women, the category of newborns and infants differed substantially for these indicators. CONCLUSIONS Due to acceptable specificity and negative predictive value, high avidity can rule out acute toxoplasmosis, but moderate sensitivity complicates the possibility of its confirmation. The results of the avidity test must be interpreted in the context of the results of other methods.
Collapse
Affiliation(s)
- Petr Kodym
- National Reference Laboratory for Toxoplasmosis, National Institute of Public Health, Prague, Czech Republic
| | - Zuzana Kurzová
- National Reference Laboratory for Toxoplasmosis, National Institute of Public Health, Prague, Czech Republic
| | - Dagmar Berenová
- National Reference Laboratory for Toxoplasmosis, National Institute of Public Health, Prague, Czech Republic
| | - Marek Malý
- National Institute of Public Health, Unit of Biostatistics, Prague, Czech Republic
| |
Collapse
|
4
|
Picone O, Fuchs F, Benoist G, Binquet C, Kieffer F, Wallon M, Wehbe K, Mandelbrot L, Villena I. Toxoplasmosis screening during pregnancy in France: Opinion of an expert panel for the CNGOF. J Gynecol Obstet Hum Reprod 2020; 49:101814. [PMID: 32428782 DOI: 10.1016/j.jogoh.2020.101814] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/12/2020] [Indexed: 11/15/2022]
Abstract
Prenatal screening to prevent congenital toxoplasmosis as performed in France for several decades has been questioned in view of the decreasing incidence of this infection and the cost of testing. The French College of Obstetrics and Gynecology mandated a multidisciplinary panel of experts to perform a reassessment of the screening program in accordance with international good practice. In France, about 70% of pregnant women are not immune to T. gondii, and 0.2-0.25% become infected during pregnancy. The risk of maternal-fetal transmission of infection is on average 25-29% and depends greatly on the gestational age at seroconversion. In case of fetal transmission, the outcome is livebirth in 95% of cases, with latent congenital toxoplasmosis in 90% of cases and symptomatic forms in 10% of cases, of which 1/3 are severe and 2/3 moderate. Biological techniques have satisfactory performance regarding serologies for the diagnosis of maternal infections and PCR on amniotic fluid for the prenatal diagnosis of congenital toxoplasmosis. Primary prevention of toxoplasmosis is based on hygiene measures that are relatively simple, but poorly implemented. In case of maternal seroconversion, there is a strong case for prenatal prophylactic treatment as soon as possible (ideally within 3 weeks of seroconversion), spiramycin before 14 weeks of gestation (WG), and with a tendency to superiority of the pyrimethamine/sulfadiazine association over spiramycin beyond 14 W G, in order to reduce the risk of symptomatic congenital toxoplasmosis. In case of congenital toxoplasmosis, prompt initiation of treatment reduces the occurrence of cerebral signs and symptoms, as well as retinal lesions. Several medico-economic evaluations of the French toxoplasmosis screening program have been conducted including an individual cost-effectiveness approach with decision analysis which concluded on the profitability of prenatal screening as carried out in France (monthly surveillance of seronegative women, prenatal treatment in case of seroconversion, termination of pregnancy in severe forms). Though most international societies do not recommend systematic screening for mainly financial reasons, if congenital toxoplasmosis appears benign in France today, it is probably thanks to screening and the possibility of early treatment of fetuses and/or newborns. Thus, the panel recommends continuing for now the program in France for prevention of congenital toxoplasmosis.
Collapse
Affiliation(s)
- Olivier Picone
- Assistance Publique-Hôpitaux de Paris, Service de Gynécologie-Obstétrique, Hôpital Louis Mourier, Colombes, France; Université de Paris; Inserm IAME-U1137, Paris, France; FHU PREMA; Groupe de Recherche sur les Infections pendant la grossesse (GRIG)
| | - Florent Fuchs
- Service de Gynécologie Obstétrique CHU de Montpellier, Hopital Arnaud de Villeneuve, Montpellier, France; Inserm, CESP Centre de recherche en Epidémiologie et Santé des Populations, U1018, Reproduction et Développement de l'enfant, 94807 Villejuif, France; EA2415: Aide à la décision médicale Personnalisée, Axe B: Méthode en épidémiologie Clinique, Université de Montpellier
| | | | - Christine Binquet
- Inserm, CIC1432, module Epidémiologie Clinique, Dijon, France; CHU Dijon-Bourgogne, Centre d'Investigation Clinique, Module Epidémiologie Clinique/Essais Cliniques, Dijon, France
| | - François Kieffer
- Assistance Publique-Hôpitaux de Paris, Service de néonatologie, Hôpital Armand Trousseau, Paris, France
| | - Martine Wallon
- Hospices Civils de Lyon, Hôpital de la Croix-Rousse, Service de Parasitologie - Mycologie Médicale, Lyon, France; Université Lyon-1, Equipe Waking, Physiologie Intégrée du Système d'éveil, Centre de Recherche en Neurosciences de Lyon (INSERM U1028 - CNRS UMR 5292), Bron, France
| | - Karl Wehbe
- Centre Hospitalier Universitaire de Strasbourg, Service de Gynécologie-Obstétrique, Strasbourg, France
| | - Laurent Mandelbrot
- Assistance Publique-Hôpitaux de Paris, Service de Gynécologie-Obstétrique, Hôpital Louis Mourier, Colombes, France; Université de Paris; Inserm IAME-U1137, Paris, France; FHU PREMA; Groupe de Recherche sur les Infections pendant la grossesse (GRIG)
| | - Isabelle Villena
- Université Reims Champagne -Ardenne, EA7510 et Centre National de Référence de la Toxoplasmose, Centre de Ressources Biologiques Toxoplasma, Service de Parasitologie-Mycologie, Centre Hospitalier Universitaire de Reims, Reims, France
| |
Collapse
|
5
|
Garnaud C, Fricker-Hidalgo H, Evengård B, Álvarez-Martínez MJ, Petersen E, Kortbeek LM, Robert-Gangneux F, Villena I, Costache C, Paul M, Meroni V, Guy E, Chiodini PL, Brenier-Pinchart MP, Pelloux H. Toxoplasma gondii-specific IgG avidity testing in pregnant women. Clin Microbiol Infect 2020; 26:1155-1160. [PMID: 32334096 DOI: 10.1016/j.cmi.2020.04.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/07/2020] [Accepted: 04/14/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND The parasite Toxoplasma gondii can cause congenital toxoplasmosis following primary infection in a pregnant woman. It is therefore important to distinguish between recent and past infection when both T. gondii-specific IgM and IgG are detected in a single serum in pregnant women. Toxoplasma gondii-specific IgG avidity testing is an essential tool to help to date the infection. However, interpretation of its results can be complex. OBJECTIVES To review the benefits and limitations of T. gondii-specific avidity testing in pregnant women, to help practitioners to interpret the results and adapt the patient management. SOURCES PubMed search with the keywords avidity, toxoplasmosis and Toxoplasma gondii for articles published from 1989 to 2019. CONTENT Toxoplasma gondii-specific IgG avidity testing remains a key tool for dating a T. gondii infection in immunocompetent pregnant women. Several commercial assays are available and display comparable performances. A high avidity result obtained on a first-trimester serum sample is indicative of a past infection, which occurred before pregnancy. To date, a low avidity result must still be considered as non-informative to date the infection, although some authors suggest that very low avidity results are highly suggestive of recent infections depending on the assay. Interpretation of low or grey zone avidity results on a first-trimester serum sample, as well as any avidity result on a second-trimester or third-trimester serum sample, is more complex and requires recourse to expert toxoplasmosis laboratories. IMPLICATIONS Although used for about 30 years, T. gondii-specific avidity testing has scarcely evolved. The same difficulties in interpretation have persisted over the years. Some authors have proposed additional thresholds to exclude an infection of <9 months, or in contrast to confirm a recent infection. Such thresholds would be of great interest to adapt management of pregnant women and avoid unnecessary treatment; however, they need confirmation and further studies.
Collapse
Affiliation(s)
- C Garnaud
- Université Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France; Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France.
| | | | - B Evengård
- Department Clinical Microbiology, Umea University, Umea, Sweden
| | - M J Álvarez-Martínez
- Microbiology Department, Hospital Clínic-ISGLOBAL, University of Barcelona, Barcelona, Spain
| | - E Petersen
- Directorate General for Disease Surveillance and Control, Ministry of Health, Oman; Institute for Clinical Medicine, Faculty of Health Science, University of Aarhus, Denmark; ESCMID Emerging Infections Task Force, ESCMID, Basel, Switzerland
| | - L M Kortbeek
- National Institute for Public Health and the Environment; Centre for Infectious Disease Control (CIb) Bilthoven, the Netherlands
| | - F Robert-Gangneux
- Université Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé Environnement et Travail)-UMR_S 1085, Rennes, France
| | - I Villena
- Université Reims Champagne-Ardenne EA 7510, CHU Reims, Centre National de Référence de La Toxoplasmose, CRB Toxoplasma, Reims, France
| | - C Costache
- Microbiology Department 'Iuliu Hatieganu', University of Medicine and Pharmacy Cluj-Napoca, Romania
| | - M Paul
- Department and Clinic of Tropical and Parasitic Diseases, University of Medical Sciences, Poznan, Poland
| | - V Meroni
- University Pavia Internal Medicine and Medical Therapy Department, Microbiology and Virology Department IRCCS, Foundation San Matteo Polyclinic, Pavia Italy
| | - E Guy
- Toxoplasma Reference Unit, Public Health Wales Microbiology, Swansea, UK
| | - P L Chiodini
- Hospital for Tropical Diseases and the London School of Hygiene and Tropical Medicine, London, UK
| | - M-P Brenier-Pinchart
- Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France; Université Grenoble Alpes, INSERM-CNRS, Institute for Advanced Biosciences, Grenoble, France
| | - H Pelloux
- Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France; Université Grenoble Alpes, INSERM-CNRS, Institute for Advanced Biosciences, Grenoble, France
| | | |
Collapse
|
6
|
How to estimate time of infection with Toxoplasma gondii in pregnant women. Use of specific IgG and IgM kinetics by 7 techniques on 691 sera. Diagn Microbiol Infect Dis 2020; 96:114987. [PMID: 32005405 DOI: 10.1016/j.diagmicrobio.2020.114987] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 11/20/2022]
Abstract
A difficulty when detecting both anti-Toxoplasma gondii-specific IgG and IgM in pregnant women is estimating the date of infection. The aim of this study was to compare the anti-Toxoplasma-specific immunoglobulin kinetics of 7 serological techniques to date the infection and to draw kinetic curves that are easy to use on a daily basis. IgG and IgM antibodies were measured on 691 sera samples. IgM appeared a few days, less than 1 week, after the beginning of the infection. Then, the levels of IgM reached a peak at approximately 3, 4, and 5 weeks with Toxo-ISAGA® IgM, IgM homemade indirect immunofluorescence assays, and Vidas Toxo® IgM, respectively. Furthermore, the Architect Toxo® IgG titers were higher than those of the Vidas Toxo® IgG results in recent infection (less than 6 months). This study provides new average IgM and IgG curves that can help to determine the approximate date of infection.
Collapse
|