NPM1 and acute myeloid leukemia: For descriptive purposes, we observed lower frequencies of HLA-B*40:01 in AML patients with co-occurring mutations in NPM1 (A or D) and DNMT3A (R882H or C) compared to patients with NPM1mutA/D and unmutated DNMT3A (n = 2 of 84 vs. n = 2 of 61, 3.2% vs. 3.3%).