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

Background: The research on endemic pemphigus foliaceus (fogo selvagem) has mainly focused on the humoral immune response, but little attention has be en given to the function of cell-mediated immune response and the nature of the cellular elements of the tissue reaction in the lesions of fogu selvag em. Objective: The purpose of this study was the immunophenotype characterizati on of the inflammatory cells as well as the expression of adhesion molecule s and HLA-DR in the perilesional and lesional skin of fogo selvagem. Methods: Twenty biopsy specimens of lesional and perilesional skin were ana lyzed by immunohistochemical techniques. The panel of monoclonal antibodies consisted of CD8, CD4, CD la, HLA-DR, IL-2R, LFA-1, ICAM-1, and PAN-B. Results: The semiquantitative analysis of the cell population revealed a pr edominance of CD4 T lymphocytes in the tissue response of perilesional and lesional skin. The population of epidermal Langerhans cells was decreased i n lesional skin when compared with the perilesional skin, whereas CD1a(+) d ermal dendritic cells predominated in lesional skin. Keratinocyte expressio n of ICAM-1 and HLA-DR was negative in both lesional and perilesional skin. Conclusion: The overall results suggest the participation of the cell-media ted immunity in endemic pemphigus foliaceus (fogo selvagem). The lack of ke ratinocyte ICAM-1 expression may be related to the pattern of cytokines sec reted by the CD4(+) T cells of the tissue reaction in fogo selvagem.