Immunohistochemical evaluation of macrophage activity and its relationship with apoptotic cell death in the polar forms of leprosy.

The objective of the present study was to investigate the correlation between macrophage activity and apoptosis in the polar forms of leprosy because the immunopathological phenomena involved in these forms are still poorly understood. For this purpose, 29 skin biopsy samples obtained from patients with the polar forms of leprosy were analyzed. Macrophage activity and apoptosis were evaluated by immunohistochemistry using lysozyme, CD68, iNOS and caspase 3 as markers. The nonparametric Mann-Whitney test and Spearman's linear correlation test were used for statistical analysis. The results suggest that the apoptosis rate is under the direct influence of macrophage activity in lesions of patients with the tuberculoid form. In contrast, in lepromatous lesions other factors seem to induce programmed cell death, possibly TGF-beta. Further studies are necessary to identify additional factors involved in the immunopathogenesis of leprosy.