SELECTIVE LOSS OF MYCOBACTERIUM-LEPRAE RESPONSIVENESS OF CIRCULATING LYMPHOCYTES IN PRIMARY NEURITIC LEPROSY

Sixteen patients with primary neuritic leprosy characterized by neural involvement in the absence of dermal lesions were studied. Eight healthy contacts from non-endemic areas formed the control group. T and B cell numbers and lymphocyte transformation responses to concanavalin A, phytohaemagglutin and purified protein derivative were not significantly decreased in the majority of the neuritic patients. There was a selective uniform lack of M. leprae induced lymphocyte transformation in this group (median stimulation index = 1.05). In 3 of the patients, the antigen specific unresponsiveness was present even after 5 yr of chemotherapy. The clinical extent of neural involvement and serum factors did not appear to contribute to the antigen specific deficit observed in this form of leprosy.