Investigation of predominant cell types and subtypes and expression of the inducible nitric oxide synthase enzyme (iNOS) in oral paracoccidioidomycosis / Estudo dos tipos e subtipos celulares predominantes e da expressão da enzima óxido nítrico sintase induzível (iNOS) na Paracoccidioidomicose Bucal

AUTOR(ES)

Aline Carvalho Batista

DATA DE PUBLICAÇÃO

2004

RESUMO

Paracoccidioidomycosis is a chronic granulomatous disease that induces a specific inflammatory and immune response. The participation of nitric oxide (NO), a product of the inducible nitric oxide synthase enzyme (iNOS), as an important fungicidal molecule against Paracoccidioides brasiliensis has been demonstrated. In order to further characterize the oral lesions of Paracoccidioidomycosis and elucidate the dynamics of the immune response occurring at the site of inflammation, iNOS+, CD45RO+ (active/memory T lymphocyte), CD3+ (T lymphocyte), CD8+ (cytolytic T lymphocyte), CD20+ (B lymphocyte) and CD68+ (macrophage) cells and mast cells were identified and quantified by immunohistochemistry in 20 samples of Oral Paracoccidioidomycosis (OP) and 8 clinically healthy oral tissues (Control), by means of immunoperoxidase. The number of viable fungi was verified in all OP samples, which were divided into five groups: 1 (1-50 yeast cells/mm2), 2 (51-100 yeast cells/mm2), 3 (101-200 yeast cells/mm2), 4 (201-400 yeast cells/mm2) and 5 (401-800 yeast cells/mm2). The results showed weak immunolabeling for iNOS in all aggregations of epithelioid and multinucleated giant cells (MNGC), as well as strong immunolabeling in scarce mononuclear (MN) cells located at the periphery of the granuloma. No significant increase was observed in the proportion of MN and MNGC iNOS+ cells in the OP groups when individually compared to the Control group. The results further demonstrated that, despite their low number, the polymorphonuclear neutrophils (PMN) found in the granulomas and micro-abscesses were strongly iNOS+ . Additionally, the investigation revealed similarity in the number of CD4+ cell between the OP groups with higher numbers of fungi (Groups 4 and 5) and the Control group. The findings suggest that low expression of iNOS by macrophages and MNGC in OP and the small number of CD4+ T cells in OP lesions with higher numbers of fungal cells may represent a failure of the local immune system, which allowed local fungal multiplication and maintenance of active oral lesions.

ASSUNTO(S)

paracoccidioidomicose brasilienses paracoccidioidomicose Óxido nítrico patologia bucal

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