Quantitative analyses of CD7, CD33, CD34, CD56, and CD123 within the FLT3-ITD/ NPM1-MUT myeloblastic/monocytic bulk AML blastic populations

Abstract

The most frequent mutations in acute myeloid leukemia (AML) - FLT3-ITD and NPM1 - are associated with a specific immunophenotype. We evaluated the levels of surface antigens in an uninvestigated AML patient population according to the combination of FLT3-ITD/NPM1 mutations. Antigen levels were calculated as the geometric mean fluorescence index (MFI) ratio between myeloblasts or monoblasts/monocytes and a negative population for the specific antigen. In myeloblastic populations, FLT3-ITD cases presented CD7^high MFI values (p < .001), while NPM1-MUT cases presented CD33^high (p < .001), and CD34^low (p < .001) MFI values. Within the monoblastic/monocytic populations, CD56^high expression was observed only in the FLT3-WT/NPM1-MUT population (p=.003). The single common antigen expression between myeloblasts and monoblasts/monocytes was CD123^high expression only within the FLT3-ITD/NPM1-MUT subgroup. Our results present a subtle influence of FLT3-ITD/NPM1 mutations upon antigen expression profiles in myeloblasts vs monoblasts/monocytes, and we described a novel correlation between the presence of NPM1 and CD56^high values within bulk leukemic monoblasts/monocytes.

Keywords: AML; FLT3-ITD; MFI; NPM1.