PREVENTION OF CHRONIC REJECTION BY DONOR-SPECIFIC BLOOD-TRANSFUSION IN A NEW MODEL OF CHRONIC CARDIAC ALLOGRAFT-REJECTION

Chronic graft rejection is now a major barrier to the long-term surviv al of cardiac transplants. A major hallmark of chronic rejection is in timal thickening of arteries in the graft leading to vascular occlusio n. Current animal models of chronic rejection generally utilize immuno suppression to prevent acute rejection of grafts disparate at major hi stocompatibility antigens or graft disparities involving minor histoco mpatibility antigens alone. In the present communication we describe a new model of chronic rejection involving grafting of PVG-R23 hearts i nto PVG-RT1(u) recipients. The R23 hearts, which differ from the RT1(u ) recipients at class II MHC, are rejected with a chronic time course and demonstrate extensive severe vascular myointimal proliferation wit hin the coronary arteries. Furthermore we demonstrate for the first ti me that donor-specific blood transfusion can prevent chronic rejection and the intimal thickening of the coronary arteries.