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.

Immunotherapy with a mixture of Mycobacterium leprae and BCG in different forms of leprosy and in Mitsuda-negative contacts.

A total of 529 weak or non-reactors to M. leprae, including Mitsuda-negative contacts and patients with leprosy, were vaccinated once or repeatedly, as necessary, with a mixture of 6 x 10(8) purified, heat-killed M. leprae and 0.01 mg to 0.2 mg of viable BCG. Clinical, histopathological and immunological criteria were used to evaluate the response of these individuals. Clinical changes, including sharper definition of borders and progressive flattening and regression of lesions, were observed in 57% of the active LL cases and 76% of the active BL cases. Histopathological study revealed infiltration of the lesions by mononuclear cells, appearance of epithelioid differentiation, and fragmentation of the microorganisms. Delayed-type skin tests with soluble antigen from purified M. leprae became positive in significant numbers of each group studied. These results demonstrate the efficacy of combined immunotherapy in low-resistance forms of leprosy and potential utility in the immunoprophylaxis of the disease.