Análise in situ da resposta imune celular das lesões de leishmaniose tegumentar americana em mucosa oral e nasal

• Autor(a) principal: Palmeiro, Mariana Reuter
• Data de Publicação: 2008
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional PUCRS
• Texto Completo: http://hdl.handle.net/10923/413
• topic: ODONTOLOGIA; ESTOMATOLOGIA CLÍNICA; LEISHMANIOSE; IMUNOISTOQUÍMICA

American Tegumentary Leishmaniasis (ATL) is a disease caused by protozoans of the genus Leishmania. It is transmitted through the bite of insects of the genus Lutzomyia. In most parts of Brazil, as the Rio de Janeiro State, the infection is caused by L. braziliensis. Two main clinical forms are described: cutaneous and mucosal leishmaniasis. Most of the human cases are in cutaneous lesions. However, despite the low frequency mucosal lesion, the magnitude of the tissue destruction and the resistance to the treatment result in a difficult following up of the patients. The nature of cells comprising the lesion environment may play a determinant role in this infection, as it has been described for other models of compartmentalization of the immune response. Studies have indicated the need for detailed investigation of the lesion microenvironment in order to establish the immunopathological picture of the infection. Thus, the study of ATL mucosal lesions might contribute to the understanding of the dynamics of the infection. In order to verify the composition of the inflammatory reaction present in mucosal lesions of ATL patients, we examined biopsies obtained from 20 patients suffering of mucosal leishmaniasis (12 with nose lesion and 8 with oral lesion), as well as 20 health donors (10 oral mucosa and 10 nasal mucosa). The mucosal tissues were analyzed by immunohistochemistry, using antibodies which recognize different subpopulations of cells (CD3, CD4, CD8, CD22, CD68, neutrophil elastase, CD1a) and inflammatory markers (CLA, Ki67, Bcl-2, NOS2, CD62E, Fas, FasL).The lesions presented an inflammatory reaction mainly consisting of T cells and macrophages. It was also observed an association between high NOS2 expression and reduced numbers of parasites, highlighting the importance of NOS2 in the elimination of parasites. The results demonstrated that the inflammatory reaction present in mucosal leishmaniasis is similar in nasal and oral mucosa, despite the tendency to be more intense in oral lesions. Moreover, the comparison of lesions and health tissue showed a significant increase of inflammatory cells in the first group. However, it was detected some inflammatory reaction in the named health tissues. These data could be the result of a continuous aggression by infectious agents and micro lesions, since mucosa is considered an immunological barrier to infections and trauma. In addition, parasites were more in oral tissues. Sice the patients having oral leishmaniasis have the tendency to frequently be diagnosed earlier than those ones having nasal lesion, the presence of parasites could be the result of lesion evolution.