How is transfusion-associated graft-versus-host disease similar to, yet different from, organ transplantation-associated graft-versus-host disease?

Graft-versus-host disease (GVHD) is a rare, usually fatal complication following blood transfusion or organ transplantation, namely transfusion-associated GVHD (TA-GVHD) and organ transplantation-associated GVHD (OA-GVHD). The dominant mechanism of GVHD is exposure to viable donor lymphocytes that are not recognized as foreign by, but able to respond to, the recipient. The clinical features and relative risk factors of either TA-GVHD or OA-GVHD are yet to be fully understood. The current review article aims to discuss and summarize the similarities and differences between TA-GVHD and OA-GVHD to gain a deeper understanding of the pathogenesis.