An Adapted Gating Strategy Integrating a Myelomonocytic Window Is Necessary For Correct Flow Cytometric Diagnosis In a Large Proportion Of AML With Mutated NPM1

Abstract Background Previously, it has been reported, that AML with mutated NPM1 is associated with a distinctive immunophenotype. In particular, low or absent expression of CD34 accompanied by high expression of CD33, and – at least in part of the cases - absence of HLA-DR expression was reported. CD45/side scatter (SSC) gating is widely used for the identification of blasts by flow cytometry (FC). Blast cell gates typically are defined by a low SSC and moderate CD45 expression. However, in a number of patients with NPM1mutation this typical blast cell gate comprises significantly lower blast percentages when compared to the morphological evaluation. In these patient samples a second popul…