[Immunological examination of patients with undetermined leprosy].

The immunological competence of eleven patients with undetermined leprosy was compared with that of ten normal volunteers of the same age and sex distribution; these controls have not had previous contact with leprosy. The following parameters were studied in peripheral blood cells: 1) percentage of lymphocyte bearing surface immunoglobulins, as revealed by immunofluorescence; 2) percentage of lymphocyte bearing complement receptors, as studied by antibody and complement coated erithrocyte rosetting; 3) percentage of T cells, as revealed by spontaneous sheep erithrocyte rosettes; 4) blastogenic and mytogenic response of cultured lymphocytes to PHA and 5) cell migration inhibition test using lepromine (80 x 10(6) bacilli/ml) as antigen. Skin reactions to lepromine were also assayed. In the six lepromine-positive patients with undetermined leprosy, no major immunological alterations could be detected. On the contrary, the five lepromine-negative patients showed important alterations which could well be considered as precursors of lepromatous leprosy.