Comparison of A60 and three glycolipid antigens in an ELISA test for tuberculosis

Objectives: To compare the diagnostic usefulness in tuberculosis of the serodiagnostic enzyme-linked immunosorbent assay (ELISA) kit A60 (Anda Biologicals, Strasbourg, France) and of our domestic ELISA based on three purified cell wall glycolipidantigens. Methods: The presence and concentrations of IgG and IgM anti-A60 antibodies and anti-LOS, anti-DAT and anti-PGLTb1 antibodies against the glycolipidantigens were determined by ELISA in 50 HIV-seronegative and 46 HIV-seropositive patients, with documented active tuberculosis. The specificity of these ELISAs was determined with use of sera from 50 healthy blood donors, 29 patients with non-mycobacterial pulmonary diseases and 24 HIV-positive patients with disseminated Mycobacterium avium infection. Results: With a calculated cut-off for each antigen and immunoglobulin that gave a specificity higher than or equal to 98%, the cumulative ELISA results showed that only 36.5% of the patients with tuberculosis had a positive response in the A60 test, as compared with 84.4% who showed a response to the three glycolipidantigens ( p + lymphocytes counts, in contrast to the results with the three glycolipidantigens. Conclusions: These results show the limitations of the A60 ELISA, and confirm the potencies of the glycolipidantigens in serodiagnosis of tuberculosis in HIV-positive and HIV-negative patients.