Graft-versus-host disease after multiorgan transplantation.

A rat model of multiorgan transplantation (MOTx) including the liver, pancreas, duodenum, and variable segments of small bowel (SB) was used to ascertain whether graft-versus-host disease (GVHD) could be produced by this procedure. Rats receiving an isogeneic multiorgan transplant (MOT) survived more than 150 days. MOTx was then performed in the Lewis to (Lewis x Brown Norway) LBNF1 semiallogeneic combination, ensuring unidirectional GVHD. En bloc transplantation of the liver, pancreas, duodenum, and entire jejunum provoked lethal GVHD in all animals, and the mean time to recipient death (MT) was 16.5 +/- 0.43. When only one-half of the jejunum was included in the MOT, lethal GVHD similarly occurred in 100% of animals and the MT was 18 +/- 0.86. Finally, when only liver, pancreas, and duodenum were transplanted, the incidence of lethal GVHD was reduced to 50% (P less than 0.1). In those rats that died of GVHD, MT was 16 +/- 0.33. Fifty percent of the rats in this group, however, recovered from a milder form of GVHD and survived more than 150 days. These results demonstrate that MOTx induces GVHD and that the lethality of this process correlates with the inclusion of the SB in the graft and thus, with the overall amount of transplanted lymphoid tissue.