[Comparative analysis of two mycobacterium tuberculosis antigens and two methodological approaches to determining serum antimycobacterial antibodies].

The glycoprotein (15-18 kDa) antigen of Mycobacterium tuberculosis H37Rv was affinity isolated on the immunosorbent with monoclonal antibodies S4C1G4 (specific to M. tuberculosis H37Rv; Avdiyenko V. G., Kondrashov S.Yu, Lyashenko S.M.@Probl. Tuberk. 1996, v. 1, p. 6-8 (in Russian). This antigen and PPD (Batch RT 45, Stattens Seruminstitute, Denmark) that was a standard antigen were used for enzyme-linked immunosorbent assay (ELISA), by detecting serum IgG antibodies in patients with pulmonary tuberculosis, and control groups of patients with lung diseases other than tuberculosis (bronchitis and/or asthma, pneumonia) as well as healthy volunteers. The diagnostic parameters of specificity and sensitivity for titers and the same parameters for optic density (OD) (in serum dilution with maximum differences for groups of patients and donors) were compared. The new monoantigen method provided 86.11% specificity and 87.87% sensitivity, which were higher those obtained for optic density (63.89 and 80%, respectively). With PPD, the specificity and sensitivity were 58.04 and 78.78 (for the new titer method) versus 50 and 78.78% (OD data). The method error for titer determination was 10% and for standard OD determination was 27%. The new approach offers additional possibilities of enhancing the quality of ELISA for diagnosis of tuberculosis.