Acute vascular rejection involving the major coronary arteries of a cardiac allograft.

A case of acute vascular rejection occurring in a cardiac allograft is presented. The rejection was characterized by prominent lymphocytic infiltration of the major coronary arteries in a pattern similar to that observed in acute vascular rejection occurring in renal allografts. Additionally, there was electron microscopic evidence of endothelial damage of smaller vessels. In addition to routine light microscopic evaluation of heart biopsies obtained in this case, immunofluorescent staining of biopsies for IgG, IgM, C3, Clq, fibrinogen, T cells, B cells, and Ia human leukocyte antigen (HLA-DR) was also performed. These studies suggest that antibodies may have been important in the terminal rejection episode described in this case. Furthermore, immunofluorescent staining detected continuing endothelial cell damage, reflected as Ia antigen positivity of allograft blood vessels, despite apparent improvement of rejection as judged by light microscopy.