Serologic response to mycobacterial proteins in hansen's patients during multidrug treatment

Humoral immune responses were studied in 24 leprosy patients treated with multidrug therapy (MDT) and 16 contacts. The patients were monitored for 2 to 3 years with repeated determination of IgG antibody levels directed to different mycobacterial proteins (Mycobacterium tuberculosis, Mt70; M. bovis, Mb65; M. leprae, Ml36, 28, 18, 10 kDa, and the complete protein M. leprae extract, MLSA). All recombinant antigens were used at 5 micrograms/ml concentration and the complete soluble M. leprae extract at 2 micrograms/ml. The results shown in this study reveal a clear decline in IgG antibodies directed toward mycobacterial proteins in the 12 multibacillary (MB) patients when they were submitted to MDT. Initially we found strong reactivity toward complete cytosolic protein and M. leprae membrane protein. The most reactive recombinant proteins in MB patients were Ml10, Ml36, Mt70 kDa and, finally, Ml18 kDa when compared to the paucibacillary (PB) group. After treatment was completed all lepromatous and borderline lepromatous patients showed low or undetectable levels as compared with their initial values before starting treatment.