We tested the synergy of donor-specific transfusion (DST) and cyclosporine (CsA) in small bowel transplantation by comparing the systemic versus portal route of DST administration in a fully allogeneic rat model. The protocol is relevant to cadaveric transplantation by conditioning only 24 hr before allografting. A 1 ml intraportal DST day -1 and low-dose CsA significantly prolonged survival (MST 53.7 +/- 17.5 days) when compared with systemic DST day -1 and low-dose CsA (MST 18.4 +/- 5.6 days). This suggests that intraportal DST can be beneficial in cadaveric SBT, as only a 24-hr induction period is necessary. We speculate that antigen trapping in the liver and interaction of the DST with Kupffer cells is central to the portal DST effect.