T-LYMPHOCYTES IN LESIONAL SKIN OF PATIENTS WITH DERMATITIS-HERPETIFORMIS

Ten patients with dermatitis herpetiformis had biopsies taken from inv olved and uninvolved skin. Monoclonal antibodies and the avidin-biotin peroxidase staining technique were used to stain for T cells and Lang erhans cells in skin sections. A significant increase in the number of CD3-positive T cells was observed in the upper dermis of involved com pared with uninvolved skin (P < 0.0005). Most of the T cells in involv ed skin were CD45RO-positive memory cells; CD4-positive T cells exceed ed the number of CD8-positive T cells by a ratio of 4:1. In addition, CD1a-positive dendritic cells were observed within the clumps of T cel ls in involved dermis in nine of the 10 patients, but were absent from the dermis of uninvolved skin. Double immunofluorescent staining demo nstrated that approximately 20-40% of the CD3-positive T cells were ac tivated, and expressed the HLA-DR antigen. These findings suggest that activated T cells are involved in the pathogenesis of dermatitis herp etiformis skin lesions.