Eritema nodoso hansênico: análise comparativa do quadro histopatológico pelas técnicas de rotina e imunofluorescência / Erythema nodosum leprosum: comparative analysis of histopathologic situation by routine and immunofluorescence technique

Com a finalidade de investigar a participaçao dos imunocomplexos (Ic) na reaçao de Eritema Nodoso Hansênico (ENH), fragmentos teciduais de 22 pacientes hansenianos reacionais foram avaliados através da técníca de imunofluorescência direta (IFD) em associaçao com técnicas histopatológicas de rotina. Os resultados demonstraram a presença de Ic em vasos e zona de membrana basal da junçao dermo-epidérmica (ZMB). A presença de Ic em vasos do derma profundo e tecido celular subcutâneo em correspondência com alteraçoes vistas sob a forma de vasculites alterativas, exsudativas e necrotizantes sugerem envolvimento destes complexos no ENH.

Experimental paracoccidioidomycosis of hamster inoculated in the cheek pouch

We comparaed the granuloma morphology and immune response of hamsters inoculated with Paracoccidioides brasiliensis (Pb) into the cheek pouch, which lacks lymphatic drainage, and the ffotpad, which is rich in lymphatics. Our objective was to better understand the modulation of Pb granuloma in an immunocompetent animal inoculated in an immunologically privileged site. The humoral immune response (ELISA) and cell mediated immunity (footpad test) became positive on days 7 and 14, respectively in animal inoculated into footpad and on days 35 and 60 in animals inoculated into the pouch. Typical epithelioid granulomas were observed at both sites on day 14. The number of fungi gradually decreased from the beginning of the experiment in footpad lesions, but only after day 35 in pouch granulomas, when cell mediated immunity was detectable. The results indicate that typical epithelioid paracoccidioidomycotic granulomas may develop in the absence of a detectable immune response; however, they are incapable of controlling fungal reproduction. Lack of lymphatic drainage delays the appearance of a detectable immune response, but with time fungi escape from the pouch, elicit an immune response and reach other organs. Our results further indicate the importance of the lymphatics in the pathogenesis of paracoccidioidomycosis.