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McIntyre S, Warner J, Rush C, Vanderven HA. Antibodies as clinical tools for tuberculosis. Front Immunol 2023; 14:1278947. [PMID: 38162666 PMCID: PMC10755875 DOI: 10.3389/fimmu.2023.1278947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/27/2023] [Indexed: 01/03/2024] Open
Abstract
Tuberculosis (TB) is a leading cause of morbidity and mortality worldwide. Global research efforts to improve TB control are hindered by insufficient understanding of the role that antibodies play in protective immunity and pathogenesis. This impacts knowledge of rational and optimal vaccine design, appropriate diagnostic biomarkers, and development of therapeutics. Traditional approaches for the prevention and diagnosis of TB may be less efficacious in high prevalence, remote, and resource-poor settings. An improved understanding of the immune response to the causative agent of TB, Mycobacterium tuberculosis (Mtb), will be crucial for developing better vaccines, therapeutics, and diagnostics. While memory CD4+ T cells and cells and cytokine interferon gamma (IFN-g) have been the main identified correlates of protection in TB, mounting evidence suggests that other types of immunity may also have important roles. TB serology has identified antibodies and functional characteristics that may help diagnose Mtb infection and distinguish between different TB disease states. To date, no serological tests meet the World Health Organization (WHO) requirements for TB diagnosis, but multiplex assays show promise for improving the sensitivity and specificity of TB serodiagnosis. Monoclonal antibody (mAb) therapies and serum passive infusion studies in murine models of TB have also demonstrated some protective outcomes. However, animal models that better reflect the human immune response to Mtb are necessary to fully assess the clinical utility of antibody-based TB prophylactics and therapeutics. Candidate TB vaccines are not designed to elicit an Mtb-specific antibody response, but evidence suggests BCG and novel TB vaccines may induce protective Mtb antibodies. The potential of the humoral immune response in TB monitoring and control is being investigated and these studies provide important insight into the functional role of antibody-mediated immunity against TB. In this review, we describe the current state of development of antibody-based clinical tools for TB, with a focus on diagnostic, therapeutic, and vaccine-based applications.
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Affiliation(s)
- Sophie McIntyre
- Biomedical Sciences and Molecular Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Douglas, QLD, Australia
| | - Jeffrey Warner
- Biomedical Sciences and Molecular Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Douglas, QLD, Australia
| | - Catherine Rush
- Biomedical Sciences and Molecular Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Douglas, QLD, Australia
| | - Hillary A. Vanderven
- Biomedical Sciences and Molecular Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Douglas, QLD, Australia
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC, Australia
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Bjerrum S, Schiller I, Dendukuri N, Kohli M, Nathavitharana RR, Zwerling AA, Denkinger CM, Steingart KR, Shah M. Lateral flow urine lipoarabinomannan assay for detecting active tuberculosis in people living with HIV. Cochrane Database Syst Rev 2019; 10:CD011420. [PMID: 31633805 PMCID: PMC6802713 DOI: 10.1002/14651858.cd011420.pub3] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The lateral flow urine lipoarabinomannan (LF-LAM) assay Alere Determine™ TB LAM Ag is recommended by the World Health Organization (WHO) to help detect active tuberculosis in HIV-positive people with severe HIV disease. This review update asks the question, "does new evidence justify the use of LF-LAM in a broader group of people?", and is part of the WHO process for updating guidance on the use of LF-LAM. OBJECTIVES To assess the accuracy of LF-LAM for the diagnosis of active tuberculosis among HIV-positive adults with signs and symptoms of tuberculosis (symptomatic participants) and among HIV-positive adults irrespective of signs and symptoms of tuberculosis (unselected participants not assessed for tuberculosis signs and symptoms).The proposed role for LF-LAM is as an add on to clinical judgement and with other tests to assist in diagnosing tuberculosis. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register; MEDLINE, Embase, Science Citation Index, Web of Science, Latin American Caribbean Health Sciences Literature, Scopus, the WHO International Clinical Trials Registry Platform, the International Standard Randomized Controlled Trial Number Registry, and ProQuest, without language restriction to 11 May 2018. SELECTION CRITERIA Randomized trials, cross-sectional, and observational cohort studies that evaluated LF-LAM for active tuberculosis (pulmonary and extrapulmonary) in HIV-positive adults. We included studies that used the manufacturer's recommended threshold for test positivity, either the updated reference card with four bands (grade 1 of 4) or the corresponding prior reference card grade with five bands (grade 2 of 5). The reference standard was culture or nucleic acid amplification test from any body site (microbiological). We considered a higher quality reference standard to be one in which two or more specimen types were evaluated for tuberculosis diagnosis and a lower quality reference standard to be one in which only one specimen type was evaluated. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data using a standardized form and REDCap electronic data capture tools. We appraised the quality of studies using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool and performed meta-analyses to estimate pooled sensitivity and specificity using a bivariate random-effects model and a Bayesian approach. We analyzed studies enrolling strictly symptomatic participants separately from those enrolling unselected participants. We investigated pre-defined sources of heterogeneity including the influence of CD4 count and clinical setting on the accuracy estimates. We assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS We included 15 unique studies (nine new studies and six studies from the original review that met the inclusion criteria): eight studies among symptomatic adults and seven studies among unselected adults. All studies were conducted in low- or middle-income countries. Risk of bias was high in the patient selection and reference standard domains, mainly because studies excluded participants unable to produce sputum and used a lower quality reference standard.Participants with tuberculosis symptomsLF-LAM pooled sensitivity (95% credible interval (CrI) ) was 42% (31% to 55%) (moderate-certainty evidence) and pooled specificity was 91% (85% to 95%) (very low-certainty evidence), (8 studies, 3449 participants, 37% with tuberculosis).For a population of 1000 people where 300 have microbiologically-confirmed tuberculosis, the utilization of LF-LAM would result in: 189 to be LF-LAM positive: of these, 63 (33%) would not have tuberculosis (false-positives); and 811 to be LF-LAM negative: of these, 174 (21%) would have tuberculosis (false-negatives).By clinical setting, pooled sensitivity was 52% (40% to 64%) among inpatients versus 29% (17% to 47%) among outpatients; and pooled specificity was 87% (78% to 93%) among inpatients versus 96% (91% to 99%) among outpatients. Stratified by CD4 cell count, pooled sensitivity increased, and specificity decreased with lower CD4 cell count.Unselected participants not assessed for signs and symptoms of tuberculosisLF-LAM pooled sensitivity was 35% (22% to 50%), (moderate-certainty evidence) and pooled specificity was 95% (89% to 96%), (low-certainty evidence), (7 studies, 3365 participants, 13% with tuberculosis).For a population of 1000 people where 100 have microbiologically-confirmed tuberculosis, the utilization of LF-LAM would result in: 80 to be LF-LAM positive: of these, 45 (56%) would not have tuberculosis (false-positives); and 920 to be LF-LAM negative: of these, 65 (7%) would have tuberculosis (false-negatives).By clinical setting, pooled sensitivity was 62% (41% to 83%) among inpatients versus 31% (18% to 47%) among outpatients; pooled specificity was 84% (48% to 96%) among inpatients versus 95% (87% to 99%) among outpatients. Stratified by CD4 cell count, pooled sensitivity increased, and specificity decreased with lower CD4 cell count. AUTHORS' CONCLUSIONS We found that LF-LAM has a sensitivity of 42% to diagnose tuberculosis in HIV-positive individuals with tuberculosis symptoms and 35% in HIV-positive individuals not assessed for tuberculosis symptoms, consistent with findings reported previously. Regardless of how people are enrolled, sensitivity is higher in inpatients and those with lower CD4 cell, but a concomitant lower specificity. As a simple point-of-care test that does not depend upon sputum evaluation, LF-LAM may assist with the diagnosis of tuberculosis, particularly when a sputum specimen cannot be produced.
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Affiliation(s)
- Stephanie Bjerrum
- University of Southern DenmarkDepartment of Clinical Research, Research Unit of Infectious DiseasesOdenseDenmark
- Odense University HospitalMyCRESD, Mycobacterial Research Centre of Southern Denmark, Department of Infectious DiseasesSdr. Boulevard 29OdenseDenmark
- Odense University HospitalOPEN, Odense Patient data Explorative NetworkOdenseDenmarkDenmark
| | - Ian Schiller
- McGill University Health Centre ‐ Research InstituteDivision of Clinical EpidemiologyMontrealQCCanada
| | - Nandini Dendukuri
- McGill University Health Centre ‐ Research InstituteDivision of Clinical EpidemiologyMontrealQCCanada
| | - Mikashmi Kohli
- McGill UniversityDepartment of Epidemiology, Biostatistics and Occupational HealthMontrealCanada
| | - Ruvandhi R Nathavitharana
- Beth Israel Deaconess Medical Center, Harvard Medical SchoolDivision of Infectious DiseasesBostonUSA
| | - Alice A Zwerling
- University of OttawaSchool of Epidemiology & Public Health600 Peter Morand Crescent, Room 301EOttawaOntarioCanadaK1G5Z3
| | - Claudia M Denkinger
- FINDGenevaSwitzerland
- University Hospital HeidelbergCenter of Infectious DiseasesHeidelbergGermany
| | - Karen R Steingart
- Department of Clinical Sciences, Liverpool School of Tropical MedicineHonorary Research FellowPembroke PlaceLiverpoolUK
| | - Maunank Shah
- John Hopkins University School of MedicineDepartment of Medicine, Division of Infectious DiseasesBaltimoreMarylandUSA
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Younis H, Kerschbaumer I, Moon JY, Kim RS, Blanc CJ, Chen T, Wood R, Lawn S, Achkar JM. Combining urine lipoarabinomannan with antibody detection as a simple non-sputum-based screening method for HIV-associated tuberculosis. PLoS One 2019; 14:e0218606. [PMID: 31237915 PMCID: PMC6592524 DOI: 10.1371/journal.pone.0218606] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 06/05/2019] [Indexed: 11/28/2022] Open
Abstract
Background Simple methods for the accurate triaging and screening of HIV-associated tuberculosis (TB) are urgently needed. We hypothesized that combining serum antibody with urine lipoarabinomannan (U-LAM) detection can improve the detection of HIV-associated TB. Methods We performed a case-control study with sampling from a prospective study of South African HIV-infected subjects who were screened for TB prior to initiating antiretroviral therapy. Sera from all available TB cases (n = 74) and randomly selected non-TB controls (n = 30), all tested for U-LAM, sputum microscopy, GeneXpert, and cultures, were evaluated for antibodies to LAM and arabinomannan (AM). Diagnostic logistic regression models for TB were developed based on the primary test results and the additive effect of antibodies with leave-one-out cross-validation. Results Antibody responses to LAM and AM correlated strongly (p<0.0001), and IgG and IgM reactivities were significantly higher in TB than non-TB patients (p<0.0001). At 80% specificity, the target specificity for a non-sputum-based simple triage/screening test determined by major TB stakeholders, combining U-LAM with IgG detection significantly increased the sensitivity for HIV-associated TB to 92% compared to 30% for U-LAM alone (p<0.001). Sputum microscopy combined with IgG detection increased sensitivity to 88% compared to 31% for microscopy alone, and Xpert with IgG increased sensitivity to 96% and 99% compared to 57% for testing one, and 70% for testing two sputa with Xpert alone, respectively. Conclusion Combining U-LAM with serum antibody detection could provide a simple low-cost method that meets the requirements for a non-sputum-based test for the screening of HIV-associated TB.
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Affiliation(s)
- Hiba Younis
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Isabell Kerschbaumer
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jee-Young Moon
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Ryung S. Kim
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Caroline J. Blanc
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Tingting Chen
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Robin Wood
- Desmond Tutu HIV Centre, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Steven Lawn
- Desmond Tutu HIV Centre, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jacqueline M. Achkar
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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Luo L, Zhu L, Yue J, Liu J, Liu G, Zhang X, Wang H, Xu Y. Antigens Rv0310c and Rv1255c are promising novel biomarkers for the diagnosis of Mycobacterium tuberculosis infection. Emerg Microbes Infect 2017; 6:e64. [PMID: 28698665 PMCID: PMC5567170 DOI: 10.1038/emi.2017.54] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/21/2017] [Accepted: 05/22/2017] [Indexed: 12/19/2022]
Abstract
This study aimed to identify novel immunogenic epitopes from Mycobacterium tuberculosis (MTB) that could be used in tuberculosis (TB) diagnostics. To determine the diagnostic potential of mycobacterial antigens in serodiagnosis of TB, 256 patients were enrolled in a study and divided into two groups: 126 smear-positive pulmonary TB patients (SPPT) and 130 smear-negative pulmonary TB patients (SNPT); 152 bacillus Calmette-Guerin (BCG)-vaccinated healthy people were used as a control. Murine results showed that antigens Rv0310c-E from RD 8 and Rv1255c-E from RD 10 were strongly immunogenic to Th1 cells and induced a great humoral response. Receiver operating characteristic analysis indicated that Rv0310c-E (area under the curve (AUC): 0.800) and Rv1255c-E (AUC: 0.808) performed better than ESAT-6 (AUC: 0.665) and CFP-10 (AUC: 0.623) proteins but were comparable with Rv3425 (AUC: 0.788) protein in a human serum IgG analysis. Rv0310c-E demonstrated the highest diagnostic ability for the SPPT group (Youden index: 0.5602, sensitivity: 69.84%, specificity: 86.18%), while Rv1255c-E demonstrated the highest diagnostic ability for the SNPT group (Youden index: 0.5674, sensitivity: 73.84%, specificity: 82.89%). In addition, combination analysis found that antigen Rv0310c-E, coupled with the Rv3425 protein (Youden index: 0.6098, sensitivity: 87.30%, specificity: 73.68%) had the strongest performance for TB diagnostics of the SPPT group, and the single antigen Rv1255c-E was strongest for the SNPT group. These results suggest that antigens Rv0310c-E and Rv1255c-E are potential antigens for TB serodiagnostic tests, which may facilitate detection of MTB in smear-negative and smear-positive patients.
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Affiliation(s)
- Liulin Luo
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China.,Department of Clinical Laboratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Lin Zhu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China
| | - Jun Yue
- Department of Clinical Laboratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Jianping Liu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China
| | - Guoyuan Liu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China
| | - Xuelian Zhang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China
| | - Honghai Wang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China
| | - Ying Xu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China
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Early diagnosis of spinal tuberculosis. J Formos Med Assoc 2016; 115:825-836. [PMID: 27522334 DOI: 10.1016/j.jfma.2016.07.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 06/28/2016] [Accepted: 07/02/2016] [Indexed: 11/23/2022] Open
Abstract
Spinal tuberculosis (STB) is a common manifestation of extrapulmonary tuberculosis (TB). STB accounts for around 2% of all cases of TB and around 15% of extrapulmonary TB cases. The World Health Organization has proposed a global strategy and targets for TB prevention, care, and control after 2015. Under this strategy, patients will receive standard care according to the recommendations and guidelines after confirmation of STB diagnosis. However, current recommendations and guidelines focus on disease and medication therapy management, and recommendations for early detection or decision-making algorithms regarding STB are lacking. In this review, we identified five key components for early diagnosis: (1) risk factors for STB; (2) common symptoms/signs of STB; (3) significant neuroradiological findings of STB; (4) significant laboratory findings of STB, including positive interferon-γ release assays and nonpyogenic evidence in initial laboratory data; and (5) significant clinical findings of STB. Individualized consideration for each patient with STB is essential, and we hope that the algorithm established in this review will provide a valuable tool for physicians who encounter cases of STB.
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Shah M, Hanrahan C, Wang ZY, Dendukuri N, Lawn SD, Denkinger CM, Steingart KR. Lateral flow urine lipoarabinomannan assay for detecting active tuberculosis in HIV-positive adults. Cochrane Database Syst Rev 2016; 2016:CD011420. [PMID: 27163343 PMCID: PMC4916932 DOI: 10.1002/14651858.cd011420.pub2] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Rapid detection of tuberculosis (TB) among people living with human immunodeficiency virus (HIV) is a global health priority. HIV-associated TB may have different clinical presentations and is challenging to diagnose. Conventional sputum tests have reduced sensitivity in HIV-positive individuals, who have higher rates of extrapulmonary TB compared with HIV-negative individuals. The lateral flow urine lipoarabinomannan assay (LF-LAM) is a new, commercially available point-of-care test that detects lipoarabinomannan (LAM), a lipopolysaccharide present in mycobacterial cell walls, in people with active TB disease. OBJECTIVES To assess the accuracy of LF-LAM for the diagnosis of active TB disease in HIV-positive adults who have signs and symptoms suggestive of TB (TB diagnosis).To assess the accuracy of LF-LAM as a screening test for active TB disease in HIV-positive adults irrespective of signs and symptoms suggestive of TB (TB screening). SEARCH METHODS We searched the following databases without language restriction on 5 February 2015: the Cochrane Infectious Diseases Group Specialized Register; MEDLINE (PubMed,1966); EMBASE (OVID, from 1980); Science Citation Index Expanded (SCI-EXPANDED, from 1900), Conference Proceedings Citation Index-Science (CPCI-S, from 1900), and BIOSIS Previews (from 1926) (all three using the Web of Science platform; MEDION; LILACS (BIREME, from 1982); SCOPUS (from 1995); the metaRegister of Controlled Trials (mRCT); the search portal of the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP); and ProQuest Dissertations & Theses A&l (from 1861). SELECTION CRITERIA Eligible study types included randomized controlled trials, cross-sectional studies, and cohort studies that determined LF-LAM accuracy for TB against a microbiological reference standard (culture or nucleic acid amplification test from any body site). A higher quality reference standard was one in which two or more specimen types were evaluated for TB, and a lower quality reference standard was one in which only one specimen type was evaluated for TB. Participants were HIV-positive people aged 15 years and older. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data from each included study using a standardized form. We appraised the quality of studies using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. We evaluated the test at two different cut-offs: (grade 1 or 2, based on the reference card scale of five intensity bands). Most analyses used grade 2, the manufacturer's currently recommended cut-off for positivity. We carried out meta-analyses to estimate pooled sensitivity and specificity using a bivariate random-effects model and estimated the models using a Bayesian approach. We determined accuracy of LF-LAM combined with sputum microscopy or Xpert® MTB/RIF. In addition, we explored the influence of CD4 count on the accuracy estimates. We assessed the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS We included 12 studies: six studies evaluated LF-LAM for TB diagnosis and six studies evaluated the test for TB screening. All studies were cross-sectional or cohort studies. Studies for TB diagnosis were largely conducted among inpatients (median CD4 range 71 to 210 cells per µL) and studies for TB screening were largely conducted among outpatients (median CD4 range 127 to 437 cells per µL). All studies were conducted in low- or middle-income countries. Only two studies for TB diagnosis (33%) and one study for TB screening (17%) used a higher quality reference standard.LF-LAM for TB diagnosis (grade 2 cut-off): meta-analyses showed median pooled sensitivity and specificity (95% credible interval (CrI)) of 45% (29% to 63%) and 92% (80% to 97%), (five studies, 2313 participants, 35% with TB, low quality evidence). The pooled sensitivity of a combination of LF-LAM and sputum microscopy (either test positive) was 59% (47% to 70%), which represented a 19% (4% to 36%) increase over sputum microscopy alone, while the pooled specificity was 92% (73% to 97%), which represented a 6% (1% to 24%) decrease from sputum microscopy alone (four studies, 1876 participants, 38% with TB). The pooled sensitivity of a combination of LF-LAM and sputum Xpert® MTB/RIF (either test positive) was 75% (61% to 87%) and represented a 13% (1% to 37%) increase over Xpert® MTB/RIF alone. The pooled specificity was 93% (81% to 97%) and represented a 4% (1% to 16%) decrease from Xpert® MTB/RIF alone (three studies, 909 participants, 36% with TB). Pooled sensitivity and specificity of LF-LAM were 56% (41% to 70%) and 90% (81% to 95%) in participants with a CD4 count of less than or equal to 100 cells per µL (five studies, 859 participants, 47% with TB) versus 26% (16% to 46%) and 92% (78% to 97%) in participants with a CD4 count greater than 100 cells per µL (five studies, 1410 participants, 30% with TB).LF-LAM for TB screening (grade 2 cut-off): for individual studies, sensitivity estimates (95% CrI) were 44% (30% to 58%), 28% (16% to 42%), and 0% (0% to 71%) and corresponding specificity estimates were 95% (92% to 97%), 94% (90% to 97%), and 95% (92% to 97%) (three studies, 1055 participants, 11% with TB, very low quality evidence). There were limited data for additional analyses.The main limitations of the review were the use of a lower quality reference standard in most included studies, and the small number of studies and participants included in the analyses. The results should, therefore, be interpreted with caution. AUTHORS' CONCLUSIONS We found that LF-LAM has low sensitivity to detect TB in adults living with HIV whether the test is used for diagnosis or screening. For TB diagnosis, the combination of LF-LAM with sputum microscopy suggests an increase in sensitivity for TB compared to either test alone, but with a decrease in specificity. In HIV-positive individuals with low CD4 counts who are seriously ill, LF-LAM may help with the diagnosis of TB.
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Affiliation(s)
- Maunank Shah
- John Hopkins University School of MedicineDepartment of Medicine, Division of Infectous DiseasesBaltimoreUSA
| | - Colleen Hanrahan
- Johns Hopkins Bloomberg School of Public HealthDepartment of Epidemiology615 N Wolfe StreetBaltimoreMarylandUSAMD 21205
| | - Zhuo Yu Wang
- McGill UniversityDepartment of Epidemiology, Biostatistics and Occupational HealthMontrealCanada
| | - Nandini Dendukuri
- McGill UniversityDepartment of Epidemiology, Biostatistics and Occupational HealthMontrealCanada
| | - Stephen D Lawn
- London School of Hygiene and Tropical MedicineDepartment of Clinical Research, Faculty of Infectious and Tropical DiseasesKeppel StreetLondonUKWC1E 7HT
| | | | - Karen R Steingart
- Liverpool School of Tropical MedicineCochrane Infectious Diseases GroupPembroke PlaceLiverpoolUK
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Identification of Novel RD1 Antigens and Their Combinations for Diagnosis of Sputum Smear-/Culture+ TB Patients. BIOMED RESEARCH INTERNATIONAL 2016; 2016:7486425. [PMID: 26885516 PMCID: PMC4739478 DOI: 10.1155/2016/7486425] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 09/30/2015] [Accepted: 11/04/2015] [Indexed: 02/07/2023]
Abstract
Rapid and accurate diagnosis of pulmonary tuberculosis (PTB) is an unresolved problem worldwide, especially for sputum smear− (S−) cases. In this study, five antigen genes including Rv3871, Rv3874, Rv3875, Rv3876, and Rv3879 were cloned from Mycobacterium tuberculosis (Mtb) RD1 and overexpressed to generate antigen fragments. These antigens and their combinations were investigated for PTB serodiagnosis. 298 serum samples were collected from active PTB patients, including 117 sputum smear+ (S+) and sputum culture+ (C+) cases, 101 S−/C+ cases, and 80 S−/C− cases. The serum IgG levels of the five antigens were measured by ELISA. Based on IgG levels, the sensitivity/specificity of Rv3871, Rv3874, Rv3875, Rv3876, and Rv3879 for PTB detection was 81.21%/74.74%, 63.09%/94.78%, 32.21%/87.37%, 62.42%/85.26%, and 83.56%/83.16%, respectively. Furthermore, the optimal result for PTB diagnosis was achieved by combining antigens Rv3871, Rv3876, and Rv3879. In addition, the IgG levels of Rv3871, Rv3876, and Rv3879 were found to be higher in S−/C+ PTB patients than in other PTB populations. More importantly, combination of the three antigens demonstrated superior diagnostic performance for both S−/C+ and S−/C− PTB. In conclusion, the combination of Rv3871, Rv3876, and Rv3879 induced higher IgG response in sputum S−/C+ PTB patients and represents a promising biomarker combination for diagnosing of PTB.
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Single Nucleotide Polymorphisms in P2X7 Gene Are Associated with Serum Immunoglobulin G Responses to Mycobacterium tuberculosis in Tuberculosis Patients. DISEASE MARKERS 2015; 2015:671272. [PMID: 26798189 PMCID: PMC4698936 DOI: 10.1155/2015/671272] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/14/2015] [Accepted: 10/18/2015] [Indexed: 01/12/2023]
Abstract
Objective. Our study investigated the association between single nucleotide polymorphisms (SNPs) in P2X7 gene and serum immunoglobulin G (IgG) responses to mycobacterium tuberculosis (MTB) in TB patients. Methods. A total of 103 TB patients were enrolled as case group and 87 healthy individuals at same geographical region as control group. The SNP detection of 1513A>C and -762T>C was performed using PCR-RFLP, and the levels of serum IgG responses to MTB in all subjects were determined. Results. AC and CC of 1513A>C and TC and CC of -762T>C had higher frequencies in case group than in control group. TB patients carrying TC and CC of -762T>C had higher positive rate of IgG responses to MTB than those carrying TT. Additionally, patients carrying TC and CC of -762T>C had more MTB in sputum than those carrying TT. Conclusion. P2X7 SNPs, 1513A>C and -762T>C, may be associated with the susceptibility to tuberculosis, and -762T>C SNP may contribute to the development of MTB. The mutant genotype of -762T>C (TC and CC) may lower human capability of phagocytosis to MTB, leading to an increased morbidity of TB.
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Tuberculosis diagnosis using immunodominant, secreted antigens of Mycobacterium tuberculosis. Tuberculosis (Edinb) 2013; 93:381-8. [PMID: 23602700 DOI: 10.1016/j.tube.2013.03.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 03/11/2013] [Accepted: 03/23/2013] [Indexed: 12/19/2022]
Abstract
Tuberculosis (TB) remains a major public health concern in most low-income countries. Hence, rapid and sensitive TB diagnostics play an important role in detecting and preventing the disease. In addition to established diagnostic methods, several new approaches have been reported. Some techniques are simple but time-consuming, while others require complex instrumentation. One prominent and readily available approach is to detect proteins that Mycobacterium tuberculosis secretes, such as Mpt64, the 6-kDa early secreted antigenic target (Esat6), the 10-kDa culture filtrate protein (Cfp10), and the antigen 85 (Ag85) complex. Although their functions are not fully understood, a growing body of molecular evidence implicates them in M. tuberculosis virulence. Currently these biomarkers are either being used or investigated for use in skin patch tests, biosensor analyses, and immunochromatographic, immunohistochemical, polymerase chain reaction-based, and enzyme-linked immunosorbent assays. This review provides a comprehensive discussion of the roles these immunodominant antigens play in M. tuberculosis pathogenesis and compares diagnostic methods based on the detection of these proteins with more established tests for TB.
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