Overview
The Donor Immune Attack
Graft versus host disease (GVHD) occurs when immunocompetent donor T lymphocytes in a graft recognise the recipient’s histocompatibility antigens as foreign.
Graft-versus-host disease (GVHD) occurs when immunocompetent donor T lymphocytes in a graft recognise the recipient’s histocompatibility antigens as foreign. The donor cells then release inflammatory cytokines and recruit further immune activity, damaging host tissues. The skin, liver, and gastrointestinal tract are the classic acute targets. GVHD is most associated with an allogeneic hematopoietic stem cell transplant, in which the graft comes from another person. It does not mean that the transplant has simply “rejected.” In rejection, the recipient attacks the graft; in GVHD, immune cells carried in the graft attack the recipient. The process can be acute, chronic, or overlapping. A day-100 cutoff is a traditional classification aid, not a safe reason to dismiss new symptoms that appear later. Acute features can occur beyond day 100, and chronic GVHD can develop with or without a previous acute episode.