On day 28 after allogeneic BMT, macroscopic findings of the skin indicated erythematous rush and alopecia (A, B). Light microscopic findings showed inflammatory cells, mainly CD3+ T-cells, infiltrating the epidermis and the hair follicle in the dermis, indicating acute GVHD in the skin (C, D: HE stain, E: CD3 stain, C: ×400, D, E: ×800). Inflammatory cells, mainly CD3+ T-cells, infiltrated the portal areas and spread to the hepatic lobules with cholangiolitis and phlebitis in the portal and central veins, indicating acute GVHD in the liver (F, G: HE stain, H: CD3 stain, F: ×400, G, H: ×800). In the colon, erosion and inflammatory cell infiltration was noted with cryptitis and infiltration of CD3+ T-cells, indicating acute GVHD in the colon (I, J: HE stain, K: CD3 stain, I: ×600, J, K: ×800).