The diagnostic test characteristics of detecting free and complex-dissociated IgG to three recombinant antigens of Mycobacteriurn tuberculosis (38-kDa, Ag16 and Ag85B), singly and in combination, were evaluated in sera from 161 tuberculous patients [smear-positive pulmonary TB (50), smear-negative pulmonary TB (pTBsm-) (60) and extrapulmonary TB (51)) and 214 control patients (mycobacteriosis (14), mycoses(14), leprosy(4), other underlying diseases (82) and healthy people (100)]. The individual antigens ranged from 25% to 42% in sensitivity and from 93 % to 96 % in specificity, while considering free IgG response. Addition of complex-dissociated antibodies against each individual antigen improved the sensitivity up to 55%. The number and levels of specific antibodies varied greatly from individual to individual. Combination of individual results for free and complex-dissociated IgG to 38-kDa, Ag16 and Ag85B offered 76% sensitivity and 83% specificity. When the three antigens were placed in the same well, the sensitivity was lower than that expected on the basis of single antigen (63%) but with a good specificity (95%), even in the group of mycobacteriosis or mycoses. The highest contribution of complex-dissociated IgG results to free IgG results was seen for the diagnosis of pTBsm- patients. In conclusion, although neither single recombinant antigen was reactive with most sera from TB patients even after the measurement of both free and complex-dissociated antibodies, the use of multi-antigen cocktails improved the diagnostic utility of the ELISA assay, allowing the identification of almost 70% of pTBsm-, with a high level of specificity; the use of additional; well selected antigens should lead to the detection of almost all patients with TB. © 2008 by The Brazilian Journal of Infectious Diseases and Contexto Publishing. All rights reserved.
CITATION STYLE
Imaz, M. S., Schmelling, M. F., Kaempfer, S., Spallek, R., & Singh, M. (2008). Serodiagnosis of tuberculosis: Specific detection of free and complex-dissociated antibodies anti-mycobacterium tuberculosis recombinant antigens. Brazilian Journal of Infectious Diseases, 12(3), 234–244. https://doi.org/10.1590/S1413-86702008000300014
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