Bone marrow transplant (BMT) is an established effective anti-cancer treatment. It is often the only hope therapeutically for many patients with certain poor-prognosis hematologic cancers (e.g. leukemias, lymphomas) and auto-immune disorders. Though BMT offers major therapeutic benefits, the procedure is burdened with a 60-80% risk of causing graft-versus-host disease (GvHD) in the recipient, a debilitating and often fatal severe rejection of patient tissues by donor T cells. A recent discovery made by Drs Claude Perreault, Denis-Claude Roy and Jean-Sébastien Delisle from the Maisonneuve-Rosemont Hospital and the Institut de Recherche en Immunologie et Cancérologie (IRIC) will pave the way for a reliable predictive diagnostic test able to determine whether donor cells are likely to cause GvHD in the recipient.