label: Graft Versus Host Disease
label_lc: graft versus host disease
description: "A reaction, which may be fatal, in an immunocompromised subject (host) who has received an antigenically incompatible tissue transplant (graft) from an immunocompetent donor. The reaction is secondary to the activation of the transplanted cells against those host tissues that express an antigen not expressed by the donor, and is seen most commonly following bone marrow transplantation; acute disease is seen after 5-40 days, and chronic disease occurs weeks to months after transplantation."