Organs affected in Graft vs Host reaction are:

GVHD occurs when immunologically competent cells or their precursors are transplanted into immunologically incompetent recipients, and the transferred cells recognize allo-antigens in the host tissues and attack them leading to destruction.. Acute GVHD occurs within days to weeks after allogeneic bone marrow transplantation. Although any organ may be affected, the major clinical manifestations result from involvement of:- The immune system Epithelia of the skin It is believed that in addition to direct cytotoxicity by CD8+ T cells, considerable damage is inflicted by cytokines released by the sensitized donor T cells.