Association of lymphocyte crossmatch and the outcome of intestinal transplantation in swine

Background: The effect of preformed antidonor antibodies have been demonstrated in various types of solid organ transplantation. However, the significance of anti-donor antibodies in intestinal transplantation remains unclear. The aim of this study is to evaluate the impact that the extent of T cell crossmatch has on the outcome of swine intestinal transplantation. Materials and methods: All studies were performed on outbred domestic male pigs weighing from 15 to 20 kg. Intestinal transplantation was performed orthotopically with an exchange of grafts between white and black pigs. FK506 was administered intravenously (0.1 mg/kg per day, POD 0-7) for immunosuppression. A lymphocyte crossmatch test was performed using the direct CDC crossmatch. The results were considered positive when more than 10% of the donor lymphocytes were killed by the recipient's serum. In addition, 0-10, 11-20, 21-30, 31-80 and 81-100% of the killed lymphocytes were classified as grade 1, 2, 4, 6 and 8, respectively. Result: A total of 34 intestinal transplantations were performed. All but one case had positive donor specific T cell crossmatches. The number of grade 2, 4, 6 and 8 cases was 11, 14, 6 and 2, respectively. Although there was a tendency towards a decreased survival according to the grade, the survival rate was not statistically different among each different grade. Moreover, the rates of acute cellular rejection and vascular complications were not significantly different among the four grades. Conclusion: These results suggest that the extent of positive T cell crossmatch is not associated with the outcome of swine intestinal transplantation.