Demonstration of mycobacterial antigens in leprosy tissues.

Biopsies from 69 patients with leprosy were stained to demonstrate mycobacterial antigens using immunoperoxidase methods. The same biopsies were cut and stained using Fite-Faraco, TRIFF and hematoxylin-eosin for classifying the patients and to demonstrate mycobacteria. Since M. leprae and BCG show extensive antigenic cross reactions, anti-BCG antibodies were used as primary antisera to demonstrate cross-reacting antigens of M. leprae. Cross-reacting mycobacterial antigens were, thus, found in all LL and BL leprosy patients. Eight out of 10 patients with indeterminate leprosy had mycobacterial antigens and 17 out of 19 BT leprosy patients were positive for antigens. In general, in the BT patients the presence of the antigen was related to the host tissue reaction; this relationship was found in only half of the patients with indeterminate leprosy studied. During ENL mycobacterial antigens were found both intra- and extra-cellularly in the inflammatory infiltrate, but the polymorphonuclear leukocyte infiltration was seen only around the extracellular perivascular antigen. In reversal reaction, the inflammatory response was towards extracellular mycobacterial antigens. After this reaction there were no antigens demonstrable.