DBY/HLA class II complexes were found to be expressed on the surface of dermal vascular endothelium as well as leukemia blasts. The downstream humoral responses and production of alloantibodies against these complexes caused cytotoxicity in the skin but also against leukemia, illustrating a potentially targetable common thread between the fine balance of GVHD and GVL. Professional illustration by Somersault18:24.