Studies on Fc-receptor-bearing mononuclear leukocytes from peripheral blood of patients with dermatitis herpetiformis.

Isopaque-Ficoll separated mononuclear cell suspensions from peripheral blood of patients with dermatitis herpetiformis (DH) and healthy controls were investigated by means of a rosette assay for Fc-receptor-bearing leukocytes (EA-RFC), peroxidase staining for monocytes (Pox) and a plaque formation assay (PFC) as well as a 51Cr release assay for cell-mediated cytotoxicity. The cell suspensions were investigated both before and after fractionation on nylon fibre columns. In the patients the mean percentage of PFC in unfractionated cell suspensions was significantly higher than in the controls. In fractionated cell suspensions both the mean percentage of EA-RFC and the mean cytotoxicity index in the 51Cr release assay were significantly lower than in the controls. There were no differences in the percentages of PFC- and Pox-positive cells in fractionated cell suspensions. The results suggest a numerical defect of circulating Fc-receptor-bearing lymphocytes as estimated both by the rosette assay and the 51Cr release assay. These data may reflect a pathogenetic role of these lymphocytes in DH.