NPM1 and acute myeloid leukemia: Accordingly, ELISPOT assay, after ex vivo stimulation with the combination of 13.9 and 14.9 peptides, revealed NPM1-mutated-specific T cells secreting IFNγ in 43/85 (50.6%) PB samples and in 34/80 (42.5%) bone marrow (BM) samples, collected from 26 NPM1-mutated AML patients.