LYMPHOCYTE-PROLIFERATION, IFN-GAMMA PRODUCTION AND LIMITING DILUTION ANALYSIS OF T-CELL RESPONSES TO ICRC AND MYCOBACTERIUM-LEPRAE ANTIGENSIN LEPROSY PATIENTS

Lymphocyte proliferative responses and interferon-gamma (IFN-gamma) pr oduction after stimulation with antigens of ICRC, Mycobacterium leprae , and purified protein derivative (PPD) were assessed in leprosy patie nts and healthy donors. The patients studied were newly diagnosed as h aving lepromatous leprosy (LL), multidrug therapy (MDT) responders (MD T-R LL), MDT nonresponders (MDT-NR LL), borderline lepromatous (BL), a nd borderline tuberculoid/tuberculoid (BT/TT) leprosy. The tuberculoid leprosy patients showed increased lymphocyte proliferation and IFN-ga mma production in response to stimulation with ICRC, M. leprae, and PP D antigens compared to other groups of LL patients and healthy donors. Although lymphocytes from LL patients showed low responses to ICRC an d M. leprae antigens, their responses to PPD were not grossly affected . MDT-R LL patients showed higher lymphocyte proliferative responses a nd IFN-gamma production after stimulation with ICRC and PPD but not wi th M. leprae antigens. Tuberculoid leprosy patients showed higher T-ce ll frequencies to ICRC and M. leprae antigens compared to MDT-R LL and MDT-NR LL patients. The increased lymphocyte proliferative responses to ICRC observed in the MDT-R LL patients was reflected in the increas ed T-cell frequency to ICRC compared to M. leprae.