Immunopathologic characterization of the tissue response in endemic pemphigus foliaceus (fogo selvagem).

Abstract

The research on endemic pemphigus foliaceus (fogo selvagem) has mainly focused on the humoral immune response, but little attention has been given to the function of cell-mediated immune response and the nature of the cellular elements of the tissue reaction in the lesions of fogo selvagem. The purpose of this study was the immunophenotype characterization of the inflammatory cells as well as the expression of adhesion molecules and HLA-DR in the perilesional and lesional skin of fogo selvagem. Twenty biopsy specimens of lesional and perilesional skin were analyzed by immunohistochemical techniques. The panel of monoclonal antibodies consisted of CD8, CD4, CD1a, HLA-DR, IL-2R, LFA-1, ICAM-1, and PAN-B. The semiquantitative analysis of the cell population revealed a predominance of CD4 T lymphocytes in the tissue response of perilesional and lesional skin. The population of epidermal Langerhans cells was decreased in lesional skin when compared with the perilesional skin, whereas CD1a(+) dermal dendritic cells predominated in lesional skin. Keratinocyte expression of ICAM-1 and HLA-DR was negative in both lesional and perilesional skin. The overall results suggest the participation of the cell-mediated immunity in endemic pemphigus foliaceus (fogo selvagem). The lack of keratinocyte ICAM-1 expression may be related to the pattern of cytokines secreted by the CD4(+) T cells of the tissue reaction in fogo selvagem.