Histologic responses in sixty multibacillary leprosy patients inoculated with autoclaved Mycobacterium leprae and live BCG.

Sixty lepromatous or borderline lepromatous patients were submitted to immunotherapy with a mixture of autoclaved Mycobacterium leprae and BCG. The histopathologic findings in skin biopsy specimens taken before and after immunotherapy were evaluated independently by six histopathologists in a workshop setting. Their pooled observations on diagnosis and classification were analyzed to assess the histopathologic changes following various periods of immunotherapy. Expressing the results as the average value of five to six independent observations, there were changes in classification of reversal or upgrading toward the tuberculoid end of the leprosy spectrum in 90.5% of the patients initially classified as lepromatous (LL), and in 83.3% of those initially classified as borderline lepromatous (BL). The histopathologic findings amply support the clinical, bacteriologic and immunological changes following immunotherapy from LL or BL, to BL, mid-borderline (BB) or even borderline tuberculoid (BT) leprosy.