Alternative definition : KEGG: Graft-versus-host disease (GVHD) pathophysiology can be summerized in a three-step
process. During step 1, the conditioning regimen (irradiation and/or chemotherapy)
leads to damage, activation of host tissues and induction of inflammatory cytokines
[tumour necrosis factor (TNF-alpha) and interleukin (IL-1)] secretion. Increased expression
of major histocompatibility complex (MHC) antigens and adhesion molecules leads to
enhancement of the recognition of host MHC and/or minor histocompatibility antigens
by mature donor T cells.;