Imunoexpressão para CD1a em lesões cutâneas na doença de Jorge Lobo

Abstract

Jorge Lobo’s disease (DJL) is a chronic infection caused by the fungus Lacazia loboi, endemic in South America, especially in the Brazilian Amazon region. The most common clinical presentation is parakeloidal lesion located mainly in the lower limbs in men who practice agricultural activity. The fungus can be identified by both mycological and anatomopathological examination. The main objective of this study was to investigate the possible role of Langerhans' cells (LC) in the pathogenesis of the disease in tissue samples from skin lesions, using immunohistochemical technique. Thirty-three medical records were selected with their respective paraffin blocks of skin biopsies from patients with DJL (group 1) registered in the dermatology service at the Federal University of Para in the period from 1955 to 2005. The control group consisted of 10 paraffin blocks from normal skin (group 2) and 42 blocks from patients with paracoccidioidomycosis (PCM) (Group 3). In the analysis of patient medical records data were collected regarding age, sex, origin, profession, location and clinical type of the lesions. Langerhans cells were identified by immunohistochemistry using anti-CD1a antibody (Serotec). Patients were mostly men (84, 8%), farmers (72. 7%) aged between 46-65 years, with predominance of parakeloidal lesions (81. 8%) in the lower limbs (45. 5%). The number of positive cells was statistically analyzed. The LC were visualized along the epidermis in all biopsies from Jorge Lobo's disease. The morphology and the number of cells, did not differ from normal skin (p> 0. 05), and was increased when compared to the PCM lesions (p <0. 05). Langerhans cells were present in Jorge Lobo’s disease skin lesions similarly to the way they are in normal skin, not suffering any numerical or morphological alterations, unlike what occurred in PCM. These results suggest that in DJL fungi probably present some escape mechanism of the local immune system to evade the antigen presentation by Langerhans’ cells.