Graft vs Host Disease

It is caused by the graft-versus-host reaction after allogeneic hematopoietic stem cell transplantation. The grounding also indicates that mismatched donor T cells can recognize recipient tissues as foreign and trigger the disease. No other specific etiologic causes are supported here.

GVHD is driven by donor immune-cell recognition of host tissues, leading to inflammatory injury in target organs. The literature grounding highlights early recruitment and infiltration of macrophages into affected tissues, with M1-polarized macrophages contributing pro-inflammatory cytokines in acute GVHD and M2 phenotypes also being relevant. Gut microbiota dysbiosis and altered microbiota-derived metabolites are also associated with GVHD and are part of the disease biology described in the supplied abstracts.

Allogeneic hematopoietic stem cell transplantation is the setting in which GVHD occurs, so exposure to this modality is the main risk context supported by the grounding. The abstracts also imply that donor-recipient HLA mismatch increases risk because mismatched donor αβ T cells can elicit graft-versus-host disease. No additional patient-level risk factors are supported by the supplied material.

Treatment is described at the level of systemic immunosuppression and skin-directed therapy. The grounding supports use of skin-directed therapies as monotherapy or as adjuncts to allow faster tapering and withdrawal of systemic immunosuppression, and it notes that steroid-refractory disease remains a challenge. It also supports emerging use of JAK inhibitors as a therapeutic class in inflammatory skin disease, including GVHD-related dermatologic management, but does not provide a consensus standard beyond immunosuppressive approaches.