Performance of Purified Antigens for Serodiagnosis of Pulmonary Tuberculosis: a Meta-Analysis

Abstract

The failure to diagnose tuberculosis (TB) accurately and rapidly is a key challenge in curbing the epidemic (45,88,116). Sputum microscopy, currently the sole diagnostic test in most areas where TB is endemic, has several limitations; in particular, the sensitivity compared with that of culture is variable (80,97,104,116), multiple patient visits are required (56,93,114), considerable technical training is necessary, and the procedure is labor-intensive (45, 65). Antibody detection tests (serological tests) are used for the diagnosis of many infectious diseases and could potentially improve the means of diagnosis of TB. These tests measure the presence of specific antibodies (most often immunoglobulin G [IgG]) directed against immunodominant antigens of the pathogen in question. Compared with microscopy, antibody detection methods may enable the rapid diagnosis of TB, as these tests have the advantages of speed (results can be available within hours), technological simplicity, and minimal training requirements. In addition, these tests can be adapted to point-of-care formats that can be implemented at lower levels of health services in low-and middle-income countries (21,22,57,65).Efforts to develop antibody detection tests for the diagnosis of TB have been under way for decades, and the performance of these tests has been well described (13,17,22,32,40,47,48,52,60,64,100,107). Several systematic reviews of these tests have been published (discussed below) (28,94,95).First-generation antibody detection tests were based on crude mixtures of constituents and products of Mycobacterium tuberculosis, for example, culture filtrate proteins and purified protein derivative, the preparation used in the tuberculin skin test. Several of these early tests had low specificities, as the tests contained antigens shared among different bacterial species (1,22,48,57). During the past two decades, an increased understanding of humoral immune responses to M. tuberculosis and the new tools of

Pesquisa de IgA contra o antígeno recombinante HspX de Mycobacterium tuberculosis no diagnóstico de tuberculose pleural

“…Another metaanalysis, conducted in 2009, evaluated the performance of serological tests for pulmonary TB. (22) In 25 studies, the mean sensitivity was found to be 40% (range, 10-90%), and the mean specificity was 96% (range, 48-100%). These values are similar to those found for the test in serum in the present study, i.e., 30% (95% CI: 16-49) and 84% (95% CI 74-83), respectively.…”

Immunological Diagnosis of Active and Latent TB

“…It is a major fraction of secreted proteins in the MTB culture filtrate and cell wall. A relatively higher sensitivity in HIV-positive tuberculosis patients (62%) than HIV-negative tuberculosis patients (53%) with a high specificity (>95%) in both groups were reported for Ag85B (Steingart et al, 2009). MPT51 is an antigen also related to the protein family of Ag85 complex.…”

“…Since enhancement of B cell immunity and production of antibody along with protective cell-mediated immunity may play an important role in the immunopathogenesis of tuberculosis, detection of specific antibodies against various mycobacterial derived antigens could also play a significant role in the diagnosis of tuberculosis. The value of various mycobacterial native or recombinant protein, lipid or different combinations of purified antigens or commercially available kits as a potential candidate of active tuberculosis sero-marker was evaluated by the ELISA method in many attempts (Abebe et al, 2007;Verma & Jain, 2007;Steingart et al, 2009). Development of a serological test with sufficient diagnostic efficacy for tuberculosis diagnosis could be very much useful tool in resource-limited countries, as the procedures are simple, relatively cost effective and can be performed rapidly.…”

Assessment of the Diagnostic Potential of Clinotech TB Screen Test for Diagnosis of Pulmonary Tuberculosis in Nigeria

“…Some of these antigens have been employed in developing commercial serological TB tests (8). Clinotech TB Screen from Clinotech Diagnostics and Pharmaceuticals, Inc, Canada, is one of such tests being distributed in several developing countries including Nigeria.…”