Induction of graft-versus-host disease by small intestinal allotransplantation in rats

Adult male (Lewis x Brown Norway) F₁ (LBNF₁) rats received heterotopic small intestinal transplants from Lewis donors. Lewis-to Lewis and LBNF₁-to-LBNF₁ isografts served as controls. All of the allograft recipients died after a median survival time of 16.2 days, but all isografted rats survived indefinitely. During the period of deterioration, allografted rats developed marked cutaneous erythema and became increasingly weak and cachectic. Histological changes of the skin, spleen, and grafts were characteristic of graft-versus-host disease (GVHD). There was a marked degree of relative splenomegaly. Injection of spleen cells obtained from LBNF₁ rats with clinical GVHD into the foot-pad of syngeneic LBNF₁ rats resulted in significant enlargement of the ipsilateral popliteal lymph node. The degree of lymph node enlargement was comparable to that induced in LBNF₁ rats by injection of normal Lewis spleen cells. These results clearly demonstrate the ability of the small intestinal allograft to cause rapid and fatal GVHD in rats that are incapable of graft rejection.