Author: Assoc Prof Patrick Emanuel, Dermatopathologist, Auckland, New Zealand, 2013.
Graft versus host disease (GVHD) usually follows bone marrow transplantation. Solid organ transplantation, blood transfusions, and maternal-fetal transfusions have also been reported to cause GVHD.
Histology of graft versus host disease
In acute GVHD, there is usually a sparse interface or lichenoidlymphocyticinfiltrate which infiltrates the epidermis (figures 1a and 2a) and involves adnexal structures (fugures 2a, 2b). There are basement membrane hydropic changes. Characteristically, the lymphocytes in the epidermis surround keratinocytes which subsequently undergo necrosis.
Attempts have been made to grade the severity of acute GVHD depending on the degree of lymphocyticinfiltration and epidermalnecrosis. Grade 0 = no inflammation, Grade 4 = dense infiltrate with separation of the epidermis from the dermis.
In chronic GVHD, the features usually resemble lichen planus with a denser infiltrate than seen in acute phase lesions. There is usually impressive keratinocytenecrosis associated with the infiltrate (figure 3). Later chronic GVHD resembles scleroderma or morphoea with thickened collagen bundles arranged parallel to the epidermis.