Associations between recurrent mutations and blast immunophenotype in acute myeloid leukemia
The immune system undoubtly plays an important role in final elimination of residual leukemic cells during acute myeloid leukemia (AML) therapy. However, the anti-leukemia immune response can be inhibited by a variety of mechanisms enabling immune escape and eventual disease relapse. We analyzed selected markers of immune escape on AML cells at diagnosis (N = 53) and used them for hierarchical clustering analysis, which yielded distinct clusters with different incidence of mutations in nucleophosmin 1 (NPM1) and in the methyltransferase DNMT3A. More detailed analysis showed that in the absence of DNMT3A mutation, NPM1 mutation is associated with decreased HLA expression and also with low levels of other markers (CLIP, PD-L1, TIM-3). On the other hand, samples with concomitant DNMT3A mutation had high CLIP surface amount suggesting reduced antigen presentation. Higher CLIP exposition was also found in patients with internal tandem duplications in FLT3 (FLT3-ITD). TIM-3 transcript correlated not only with TIM-3 protein surface amount, but also with CLIP and PD-L1, suggesting acquisition of a complex immunoresistant phenotype. Our results indicate that AML genotype is to some extent related to the blast immunophenotype, and the established predictive values of particular mutations might also reflect an inherent cell resistance to the immune system.