The high frequency of NPM1wt-specific T cells may suggest that they were memory T cells generated by the donor in response to a heterologous antigen and that, after transplantation, they cross-reacted with NPM1wt peptides derived from AML blasts in the context of the allo-HLA-A*11:01 molecule. The gene discussed is HLA-A; the disease is acute myeloid leukemia.