FUT1 and leukemia: Specifically, when a HCT recipient has a homozygous or heterozygous polymorphism that encodes a minor H antigen and their HLA-matched donor is homozygous for the “negative” allele, the donor may have T cells in their repertoire that recognize the minor H antigen peptide/HLA complex on the recipient's leukemia cell surface, and those cells may eliminate any residual leukemia after HCT (Figure 1).