The role of drug timing and histoincompatibility barrier in prolongation of cardiac graft survival in mice treated with donor-specific blood and cyclophosphamide

In the H-2-compatible donor-recipient combination (BALB/c----DBA/2), pretransplant donor-specific blood transfusion (DST) significantly prolonged graft survival. Concomitant use of immunosuppression by cyclophosphamide (CY) brought about potentiation of DST effect, resulting in long-term graft survival. In contrast, in the 'strong' H-2-incompatible combination (BALB/c----CBA/H) pretreatment of the recipients with donor-specific blood resulted in hyperacute graft rejection or in impairment of drug-induced immunosuppression when DST was used with a single dose of CY. In this model however, combination of DST with both pre- and posttransplant CY immunosuppression interacted beneficially to produce significant donor-specific prolongation of graft survival.