Immunohistochemical observation of lysozyme in macrophages in leprosy

Lysozyme activities of skin granulomas of 24 patients in leprosy were studied. Lepra cells of all 15 lepromatous leprosy showed strong lysozyme activity in cytoplasma. In the specimens stained with lysozyme and Ziehl-Neelsen's carbolfuchsin double stain conspicuous lysozyme activity around M. leprae were observed. One borderline case was negative. Lysozyme of epithelioid cells and giant cells of 10 tuberculoid types were completely negative. These results suggest that lysozyme plays only a small role in the disposal of M. leprae in macrophages and other mechanisms than bacteriolytic function of lysozyme are responsible for the defence against these bacilli.