Prevention of the acute graft-versus-host disease (GVHD) in rats by the immunomodulating drug leflunomide.

The grafting of immunocompetent allogeneic cells into MHC-discordant, genetically nonresponsive F1 hybrids of inbred rat strains consistently leads to an acute, lethal graft-versus-host disease (GVHD). The novel immunomodulating drug leflunomide, which has been shown to be efficacious in animal models of autoimmunity and adverse transplantation reactions, was studied in a rat model of GVHD. It was found that this drug not only was a powerful agent to prevent this otherwise terminal disorder, but was also proficient when used as a therapy of an established GVHD. Since leflunomide has been shown to be efficacious and safe in patients with chronic rheumatoid arthritis, it would also be reasonable to investigate this drug in clinical trials for bone marrow transplantation and GVHD in human beings.