Leishmanial antigens in the diagnosis of active lesions and ancient scars of American tegumentary leishmaniasis patients

Cutaneous biopsies (n = 94) obtained from 88 patients with American tegumen tary leishmaniasis were studied by conventional and immunohistochemical tec hniques. Specimens were distributed as active lesions of cutaneous leishman iasis (n = 53) (Group I), cicatricial lesions of cutaneous leishmaniasis (n = 35) (Group II) and suggestive scars of healed mucosal leishmaniasis pati ents (n = 6) (Group III). In addition, active cutaneous lesions of other et iology (n = 24) (Group C1) and cutaneous scars not related to leishmaniasis (n = 10) (Group C2) were also included in the protocol. Amastigotes in Gro up I biopsies were detected by routine histopathological exam (30.2%), impr int (28.2%), culture (43.4%), immunofluorescence (41.4%) and immunoperoxida se (58.5%) techniques; and by the five methods together (79.3%). In Group I I, 5.7% of cultures were positive. Leishmanial antigen was also seen in the cytoplasm of macrophages and giant cells (cellular pattern), vessel walls (vascular pattern) and dermal nerves (neural pattern). Positive reaction wa s detected in 49 (92.5%), 20 (57%) and 4 (67%) biopsies of Groups I, II and III, respectively. Antigen persistency in cicatricial tissue may be relate d to immunoprotection or on the contrary, to the development of late lesion s. We suggest that the cellular, vascular and neural patterns could be appl ied in the immunodiagnosis of active and cicatricial lesions in which leish maniasis is suspected.