Antibodies to Mycobacterium tuberculosis‐specific epitopes in lepromatous leprosy

Abstract

Sera from patients with leprosy or tuberculosis and healthy subjects have been analysed for the presence of antibodies to four species‐specific mycobacterial epitopes, four different viruses and five autoantigens. Antibodies to the Mycobacterium leprae‐specific 35‐kD protein and phenolic glycolipid I epitopes were not present in patients with active pulmonary tuberculosis. In contrast, antibody levels to species‐specific epitopes of the 38‐kD and 14‐kD antigens M. tuberculosis were significantly elevated in patients with lepromatous leprosy. Neither of the two antigens is cross‐reactive with M. leprae at the B cell level. However, it was considered that cross‐reactive helper T cells could recall the response of M. tuberculosis‐specific memory B cells, which had been primed through prior self‐healing tuberculous infection. As an alternative explanation, the possible role of polyclonal B cell stimulation was considered. This seemed unlikely, however, since: (i) antibody levels to autoantigens, except anti‐smooth muscle, were not elevated, and (ii) antibody levels to four distinct viruses, unlike those to all mycobacterial epitopes, showed no correlation with litres, to M. tuberculosis‐specific epitopes. Copyright © 1991, Wiley Blackwell. All rights reserved