Specific immunosuppression in cardiac allografting using antithymocyte sera and soluble transplantation antigen

Two techniques of specific immunosuppression, using antithymocyte globulin (ATG) alone and in combination with soluble transplantation antigen (STA) prior to treatment, were studied in heterotopic outbred canine cardiac allografts. Both techniques resulted in prolonged survival of dogs having cardiac allografts with a low incidence of infections and drug toxicity complications as compared to animals treated with Prednisone and Imuran. This study demonstrates the ability of short-course ATG treatment to produce long-term (greater than 2 to 3 months) cardiac allograft survival without chronic immunosuppression. Combined ATG and STA pretreatment gave the longest allograft survival (mean, 93 days) in a small group of animals. This improved allograft survival, associated with a reduction in infections and drug toxicity complications, suggests that these techniques of specific immunosuppression may have the potential for improving survival and reducing the complications of immunosuppressive therapy following cardiac transplantation.