Problems in absorption and immunosuppression after entire intestinal allotransplantation

Orthotopic entire small intestine allografts were transplanted in twenty dogs. Ten of these animals received immunosuppressive drugs. Allograft function was compared with that of other dogs subjected to complete intestinal denervation and lymphatic interruption. Dogs with denervated intestine showed decreased d-xylose absorption with reversal to normal rates within four months. Groups receiving allografts also showed depressed function which persisted for up to five weeks. Interestingly, dogs with untreated allografts showed no significant pathologic changes even though survival ranged from one to four weeks. In contrast, some dogs who received immunosuppressive drugs showed manifestations of organ rejection. Although we could not clearly demonstrate a graft versus host reaction in untreated allografts, it appears that entire small intestinal allografts, in the absence of these immunosuppressive drugs, can precipitate such a reaction. This phenomenon is believed to be related to the abundant lymphatic tissue found in the intestine.