Vascular endothelial cell HLA-DR antigen and myocyte necrosis in human allograft rejection.

Endomyocardial biopsies were obtained from patients who had received a human heart allograft. The biopsies were stained with a monoclonal antibody to the HLA-DR framework structure and the presence of HLA-DR was determined by an immunoperoxidase staining procedure. An increase in the concentration of HLA-DR on the vascular endothelium was detected shortly after transplantation. Low concentrations of endothelial DR were rarely (1/13) associated with myocyte necrosis. Eleven of 36 biopsies having an increased concentration of vascular endothelial cell DR antigen had myocyte necrosis. This study established that rejection is associated with an increase in HLA-DR antigens on the vascular endothelial cells.