The influence of donor and recipient strains in isolated small bowel transplantation in rats.

W E recently reported that intestinal transplantation from Lewis (LEW) to Brown Norway (BN) was intractable to FK 506 therapy because of a high incidence of a graft-versus-host disease (GVHD) syndrome) similar to that in the parent to F) hybrid offspring experiments of Monchik and Russell.2 However, transplantation in the opposite direction (BN to LEW) was highly successful without either GVHD or difficult rejection reactions. Genetic analysis did not provide an explanation for the directional difference, in spite of the fact that genetic factors are known to control alloreactions.3 .4 Consequently, we undertook the experiments herein reported to determine the influence on intestinal transplant outcome of 12 donorrecipient combinations of 4 fully allogeneic rat strains, with or without a 2-week induction course of FK 506. The outcome indices of rejection and GVHD proved to be influenced overwhelmingly by the choice of the recipient strain, with the choice of the donor being a far less consequential factor.