Class II antigen expression by keratinocytes and enterocytes--an early feature of graft-versus-host-disease.

HLA-DR expression by keratinocytes and enterocytes was studied in 23 patients undergoing BMT (12 autologous; 11 allogeneic). Two monoclonal antibodies were used to detect the HLA-DR antigen. Only in two patients before transplant and in one following autologous BMT was HLA-DR expressed on keratinocytes. Of 11 allogeneic recipients, 7 developed clinical GVHD, and HLA-DR-positive keratinocytes were seen in 6 of these. HLA-DR was expressed by enterocytes in 5 patients with GVHD and 4 of these also showed HLA-DR expression by keratinocytes. HLA-DR expression by keratinocytes correlated well with clinical GVHD. Expression of this antigen by enterocytes was associated with characteristic histological appearances of GVHD, even in the absence of intestinal symptoms. A combination of traditional and immunocytochemical techniques offers a sensitive and accurate method of confirming GVHD before it becomes florid.