SHORT-COURSE CYCLOSPORINE-A THERAPY FOR DEFINITE ALLOGRAFT VALVE SURVIVAL IMMUNOSUPPRESSION IN ALLOGRAFT VALVE OPERATIONS

This study was designed to determine the effect of short-course cyclos porin A therapy (10 mg/kg daily for 14 days) on allograft valve surviv al across the histocompatibility barriers in the following rat models: (1) syngeneic Lewis to Lewis (herein referred to as autografts), (2) weakly allogeneic AS to Lewis (RT1 compatible, non-RT1-incompatible), and (3) strongly allogeneic CAP to Lewis (RT1 and non-RT1-incompatible ). Cyclosporin A-treated and untreated recipient animals (Lewis) recei ved allovital and antibiotic-treated viable allografts implanted into the infrarenal aorta. Second-set skin grafting was performed 3 weeks a fter heterotopic valve implantation to test for immunogenicity and pre sensitization. The animals (Lewis) were sacrificed serially on days 20 , 50, 100, and 150 for immunofluorescence study using mouse monoclonal antibodies (OX6) directed at class II endothelial surface antigens. T he allografts in weakly allogeneic strains showed no humoral response under a short course of cyclosporin A. The cyclosporin A-untreated all ovital grafts and the viable (antibiotic-treated) valves demonstrated fibrocalcification on the 100th and 150th postoperative days, respecti vely. In conclusion, it seems that a short course of nontoxic immunosu ppression could arrest allograft rejection and thus prevent early dege neration of allografts. Furthermore, antibiotic-treated viable allogra fts seemed to be more durable than allovital grafts.