Recent works have demonstrated that mast cells may have an important role in immunologic reactions and
inflammation once they synthesize and secrete many
cytokines including
IL4,
IL5,
IL6 and
TNF-alpha. We have conducted research in order to verify if mast cells would participate in the local inflammatory immune response against Paracoccidioides brasiliensis in skin lesions characterized by a Th2 pattern of
cytokines. Fifty-nine skin biopsies with previous histopathological diagnosis of
paracoccidioidomycosis and immunohistochemical characterization of
cytokines present in the inflammatory infiltrate were classified in three groups: group 1 (G1), with compact
granuloma and a Th1 pattern of
cytokines; group 2 (G2), with loose
granuloma and a Th2 pattern of
cytokines; group 3 (G3), both kind of
granuloma in the same lesion, characterized by
cytokines from Th1 and Th2 patterns. Ten biopsies from normal skin were used as control group. Mast cells were visualized and quantified by a
toluidine blue/HCl staining and a double immunostaining was performed to detect a co-localization of mast cells and
IL10. G2 presented an increased number of mast cells when compared to G1, G3 and control group and we frequently could find mast cells expressing
IL10 in G2. The data obtained suggest that mast cells participate in the immune response against P. brasiliensis in skin lesions with loose
granuloma and a Th2 pattern of
cytokines. Considering these results, mast cells could constitute a source of
IL10, contributing to a non-effective response against
fungal antigens.