The ultrastructural morphology of human cutaneous leishmaniasis of low parasite load.

The ultrastructural morphology of the inflammatory infiltrate in cutaneous leishmaniasis with low parasite load from seven patients was studied. Cells of the mononuclear phagocyte system (macrophages and epithelioid cells), plasma cells, and lymphocytes formed the infiltrate. Disseminated shrinkage necrosis or apoptotis as well as coagulative necrosis with loss of the plasma membrane of single macrophages occurred. An intimate contact was observed between macrophages and lymphocytes. The relationship of the morphological alterations to the persistence of the chronic inflammatory reaction and the possible explanations of the macrophage necrosis are discussed.