Graft-versus-host disease (GVHD) is a lethal complication of allogeneic hematopoietic stem cell transplantation (HSCT) where immunocompetent donor T cells attack the genetically disparate host cells. GVHD pathophysiology can be summerized in a three-step process. Step 1 involves the development of an inflammatory milieu resulting from damage in the host tissues induced by the preparative chemotherapy or radiotherapy regimen. Damaged tissues secrete inflammatory cytokines, including interleukin 1 (IL-1), and tumor necrosis factor (TNF-alpha ). During step 2, antigen-presenting cells (APCs) trigger the activation of donor-derived T cells, which induce further T-cell expansion, induce cytotoxic T lymphocytes (CTL) and natural killer (NK) cells responses and prime additional mononuclear phagocytes to produce TNF-alpha and IL-1. Also, nitric oxide (NO) is produced by activated macrophages, and it may contribute to the tissue damage seen during step 3. During step 3, the effector phase, activated CTL and NK cells mediate cytotoxicity against target host cells through Fas-Fas ligand interactions and perforin-granzyme B.
Category
Immune system disease
Brite
Human diseases in ICD-11 classification [BR:br08403]
04 Diseases of the immune system
Certain disorders involving the immune system
4B24 Graft-versus-host disease
H00084 Graft-versus-host disease
Pathway-based classification of diseases [BR:br08402]
Cellular process
nt06535 Efferocytosis
H00084 Graft-versus-host disease
