Evaluation of ID-PaGIA syphilis antibody test.

BACKGROUND: Laboratory diagnosis of syphilis is usually accomplished by serology. There are currently a large number of different commercial treponemal tests available that vary in format, sensitivity and specificity. AIM: To evaluate the ID-PaGIA Syphilis Antibody Test as an alternative to other specific treponemal tests for primary screening or confirmation of diagnosis. METHODS: Serum samples from healthy adults (n = 100) were used for detection of specificity of ID-PaGIA. To evaluate sensitivity of ID-PaGIA serum samples (n = 101) from patients with confirmed or suspected syphilis were tested for syphilis antibodies with FTA-Abs IgM, ID-PaGIA, ELISA IgM and TPHA tests. RESULTS: No false-positive results were found with ID-PaGIA. Sensitivity of various treponemal tests was the following: FTA-Abs IgM: 95.5%, ID-PaGIA and ELISA IgM: 94%, and TPHA 75%. The positive and negative predictive values of ID-PaGIA were 100 and 89.5%, respectively. CONCLUSIONS: Compared with other treponemal tests ID-PaGIA has excellent sensitivity and specificity.

[Cytokines and leprosy]. / Cytokines et lèpre.

One of the functions expressed by the effectors of the immune system is the synthesis of cytokines, either in soluble form or associated with the membrane. Study of this communication network between the different compartments of the immune system can be conducted either in the blood (serum) of leprosy patients or directly in the infected tissues. The key to how the immune response will develop lies in the nature of the cytokines produced locally by the immune cells. For the characterization and detection of cytokines/lymphokines we may use either biological methods (bioassay), or antibody-based detection systems (RIA, Elisa, Elispot, immunocytochemistry using monoclonal antibodies), or techniques derived from molecular biology (Polymerase chain reaction-PCR, analysis of messenger RNA, and hybridization in situ). These various techniques, whose advantages and disadvantages are discussed, have demonstrated that locally, in the infected lesions, resistance and/or susceptibility to M. leprae infection correlates with differing cytokine secretion profiles.

Association of mycobacterial-specific and Mycobacterium leprae specific antibody levels with clinical activity in tuberculoid leprosy: a comparative study of three serological enzyme-immunoassays.

The ELISAs for polyclonal antibodies against Mycobacterium leprae (ML-ELISA) and specific antibodies against epitopes on 35 kDa protein (SACT-ELISA) and phenolic glycolipid I (PG-ELISA) of M. leprae were evaluated comparatively in a group of 88 tuberculoid leprosy patients. The overall seropositivity rate with a battery of 3 tests (68%) was not significantly higher than that obtained with ML-ELISA alone (55%) for IgG class of antibodies. Seropositivities for SACT-ELISA and PG-ELISA were, respectively, 38% and 26%. ML-ELISA for IgM class of antibodies was least sensitive, showing only 8% positivity. A significant correlation was noted between individual values of the three assays, but the positive proportions overlapped maximally in the case of ML-ELISA (IgG) and SACT-ELISA. Further, positivity for the latter two assays, particularly SACT-ELISA, showed significant associations with the extent of 'active' (largely untreated) infection. Immunoblotting revealed that the main antibody response was directed towards M. leprae antigens in the molecular weight range of 20-40 kDa and the densitometry results of this zone correlated significantly with corresponding SACT-ELISA and ML-ELISA (IgG) values.