[Conflicting xenograft. Role of preoperative total lymphoid irradiation]

This study deals with an experimental model of discordant cardiac xenograft between 24 donor lambs of the Préalpes race and 24 recipient Camborough pigs divided up into 4 groups: I control (6) without immunosuppressive treatment; II (5) with pharmacological immunosuppression (IP); III (13) with PI and total lymphoid irradiation (TLI) and immediate graft, divided up into IIIa (5) with high-rate (HR) TLI and IIIb with low-rate (LR) TLI; IV (4) with a two-week lapse between TLI and grafting. The best graft survival rate (GSR) is obtained either after delayed LR-TLI or after LR-TLI without delay. This study seems to be the first one demonstrating that for discordant xenogenic grafts, TLI associated to PI with cyclosporin A (Cy A) significantly prolongs the survival of the graft (30 times).