Allograft Rejection of Small Bowel Transplantation in Pigs

n = 9): nonimmunosuppressed recipients; (2) group 2 (n = 8): FK506-immunosuppressed recipients; (3) group 3 (n = 2): autotransplant controls; and (4) donors (n = 17). Orthotopic small bowel transplantations were performed with Thiry-Vella loops for daily biopsies. The survival rate of group 2 was significantly longer than that of group 1 (P < 0.05). One best survivor in group 2 was killed at postoperative day (POD) 365. Treatment by FK506 prevented rejection, but most of the pigs died of pneumonia. In group 1, rejection began on POD 3 and progressed to severe rejection rapidly within 7 days. In group 2, rejection began from POD 6 to POD 8, but either remained mild or spontaneously improved. The differences in the routine laboratory data and the tumor necrosis factor-α level were not evident between the groups. Histological studies of repeated graft biopsies are thus considered to be essential for detecting signs of graft rejection. (Received for publication on Mar. 26, 1997; accepted on Jan. 6, 1998)