Follow-up of multibacillary leprosy patients using a phenolic glycolipid-I-based ELISA. Do increasing ELISA-values after discontinuation of treatment indicate relapse?

With the introduction of reproducible serological tests it was hoped that relapses in leprosy patients, after discontinuing treatment, could be detected before damaging reactions occurred and before the patients became infectious. The possible value of an ELISA using a semisynthetic analogue of phenolic glycolipid-I to detect antibodies to this antigen in order to predict a relapse in multibacillary patients was investigated. In contrast to that reported for paucibacillary patients, this test was useful to detect early relapses in multibacillary patients. In 3 out of 4 multibacillary patients who relapsed, the ELISA-values were increased. The decreased ELISA-values in the one relapsed patient could be attributed to the corticosteroid therapy. In the multibacillary patients who did not relapse after RFT, the ELISA-values were consistently low or decreased. In only one patient did the ELISA-values increase following his release from treatment and this patient was clinically suspected of developing a relapse.

Immunochemical characterization of Mycobacterium leprae antigens by the SDS-polyacrylamide gel electrophoresis immunoperoxidase technique (SGIP) using patients' sera.

In this study the SDS-polyacrylamide gel electrophoresis immunoperoxidase (SGIP) assay was used for characterizing the antigenic components of Mycobacterium leprae using patients' sera. This technique involved the separation of mycobacterial sonicates on SDS-polyacrylamide gels, longitudinal sectioning of the gels, incubation with patients' sera and visualization of the antigen-antibody complexes by the indirect immunoperoxidase technique. A number of antigens present in M. leprae sonicates were recognized by leprosy patients' sera, some of which were seen in other mycobacteria as well. Antibody binding to a 33 kD antigen, present in both M. leprae and BCG sonicates, was reduced only in the latter after 6 months of multiple drug treatment of one patient. It is suggested that this is a common mycobacterial antigen with one or more M. leprae specific determinants. Several antigens were identified only in M. leprae sonicates, only by leprosy patients: a 12, 22, 28, 36, 41 and 86 kD component. These antigens lost their antigenicity after trypsin treatment, but were heat stable. Such M. leprae specific antigens may be useful for immunodiagnosis.