MPO and Pancytopenia: Nagai et al. [1] proposed the following diagnostic criteria: pancytopenia with rare appearance of blasts in peripheral blood; less than 40% bone marrow hypocellularity; more than 30% blasts in bone marrow of all nucleated cells; and myeloid phenotypes of leukemic blasts by myeloperoxidase staining and/or immunophenotyping.