Where there is skin involvement, test for chimerism by STR using affected and unaffected skin biopsies to detect donor chimerism in the affected skin. Where there is no skin involvement then a blood sample may be tested to look for donor chimerism with a buccal sample providing the patient type.

Most treatment options have not proved very effective but options include support of haematopoiesis with cytokines and discontinuation of antibiotics or any drugs that might be myelosuppressive.

Transfusion Associated Graft versus Host Disease (TA-GvHD) is a rare complication of blood transfusion which occurs when immunocompetent leucocytes, which are incompatible with the recipient in the graft versus host direction, are transfused into a recipient who is unable to mount an immune response against the leucocytes due to them being compatible in the host versus graft direction and/or the patient being immunocompromised. This allows engraftment of the transfused leucocytes which then proceed to reject the host. TA-GvHD risk is also high in directed donations from related donors as well as in transfusion with HLA matched blood products.

TA-GvHD presents with the same symptoms as bone marrow associated GvHD but typically has a much more rapid onset. The difference with BMT GvHD is that whereas following a bone marrow transplant, the recipient marrow is of donor origin and is not attacked by the GvHD, in TA-GvHD, the majority of the marrow is of recipient origin and is attacked by the TA-GvHD leading to a hypocellular bone marrow and ultimately to bone marrow failure. Prognosis for TA-GvHD is poor.