DETECTION OF TRANSFORMING GROWTH-FACTOR-BETA-1 IN DERMAL LESIONS OF DIFFERENT CLINICAL FORMS OF LEPROSY

Immunohistochemical studies were performed to determine the presence a nd distribution of polypeptide transforming growth factor (TGF)-beta 1 , a cytokine with macrophage-suppressing activity, in skin biopsies fr om 41 patients with different clinical forms of leprosy. We used an an ti-TGF-beta 1 polyclonal antibody and the avidin-biotin-peroxidase (AB C complex) method. The results demonstrated that the lesions of the le promatous and borderline lepromatous forms presented intense cytoplasm staining for TGF-beta 1 in the cells of the dermal infiltrate. A reac tion of moderate intensity was observed in the cells of granulomas fro m borderline borderline cases, whereas no detectable immunoreaction wa s observed in granuloma cells from the tuberculoid and borderline tube rculoid forms. Considering that in the lepromatous leprosy form Mycoba cterium leprae multiplies ia the cytoplasm of macrophages and the lesi ons are diffuse and consist of poorly differentiated young macrophages , we believe that these alterations may be explained at least in part by the presence of TGF-beta 1 in the dermal infiltrate. Production of the cytokine may be induced by the presence of the bacillus itself and of its constituents, causing a mechanism of parasite evasion. Similar ly, the absence of TGF-beta 1 in tuberculoid leprosy, which progresses with a specific immune response to M. leprae, may explain the intense differentiation of macrophage cells with the formation of well define d epithelioid granulomas capable of eliminating most of the bacilli.