[Immunocytochemical investigations of cardiac and vessel allograft arteriosclerosis using smooth muscle cell and macrophage-specific monoclonal antibodies].

Accelerated coronary arteriosclerosis is one of the major complications affecting long-term survival in cardiac transplantation. In this study, we sought to clarify the cellular components in cardiac and vessel allograft arteriosclerotic lesions using monoclonal antibodies specific to either the muscle actin (HHF 35) or the macrophage (RAM 11). Four kinds of allogeneic transplantations were performed in the rabbits: 1) cardiac heterotopic transplantations, low cholesterol-fed (n = 6), 2) cardiac heterotopic transplantations, 1% cholesterol-fed (n = 6), 3) vessel transplantations, low cholesterol-fed (n = 6), 4) vessel transplantations, 1% cholesterol-fed (n = 6). All recipients were immunosuppressed with cyclosporine. The donor hearts and the arterial grafts were excised 5 weeks after transplantation and submitted to immunocytochemical analysis. The intimal lesions in both groups 1 and 3 were composed of infiltrating mononuclear cells and HHF 35 positive smooth muscle cells. The more thickened intima in both groups 2 and 4 were occupied with smooth muscle cells and foam cells, which were derived from macrophages. These data suggest that the proliferation of smooth muscle cells might be a major factor contributing to graft arteriosclerosis, and that long term exposure to hypercholesterolemia could induce the accumulation of smooth muscle cells or macrophage derived foam cells.