The immune system is important for elimination of residual leukemic cells during acute myeloid leukemia (AML) therapy. Anti-leukemia immune response can be inhibited by various mechanisms leading to immune evasion and disease relapse. Selected markers of immune escape were analyzed on AML cells from leukapheresis at diagnosis (N = 53). Hierarchical clustering of AML immunophenotypes yielded distinct genetic clusters. In the absence of DNMT3A mutation, NPM1 mutation was associated with decreased HLA expression and low levels of other markers (CLIP, PD-L1, TIM-3). Analysis of an independent cohort confirmed decreased levels of HLA transcripts in patients with NPM1 mutation. Samples with combined NPM1 and DNMT3A mutations had high CLIP surface amount suggesting reduced antigen presentation. TIM-3 transcript correlated not only with TIM-3 surface protein but also with CLIP and PD-L1. In our cohort, high levels of TIM-3/PD-L1/CLIP were associated with lower survival. Our results suggest that AML genotype is related to blast immunophenotype, and that high TIM-3 transcript levels in AML blasts could be a marker of immune escape. Cellular pathways regulating resistance to the immune system might contribute to the predicted response to standard therapy of patients in specific AML subgroups and should be targeted to improve AML treatment.

• Keywords
• AML, DNMT3A, NPM1, TIM-3, immunophenotype,
• MeSH
• Leukemia, Myeloid, Acute * diagnosis   genetics   MeSH
• B7-H1 Antigen genetics   MeSH
• Biomarkers MeSH
• Hepatitis A Virus Cellular Receptor 2 genetics   MeSH
• DNA Methyltransferase 3A * genetics   MeSH
• Humans MeSH
• Mutation MeSH
• Nucleophosmin * genetics   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• B7-H1 Antigen MeSH
• Biomarkers MeSH
• Hepatitis A Virus Cellular Receptor 2 MeSH
• DNA Methyltransferase 3A * MeSH
• DNMT3A protein, human MeSH Browser
• NPM1 protein, human MeSH Browser
• Nucleophosmin * MeSH

Compared to solid tumors, the role of PD-L1 in hematological malignancies is less explored, and the knowledge in this area is mostly limited to lymphomas. However, several studies indicated that PD-L1 is also overexpressed in myeloid malignancies. Successful treatment of the acute myeloid leukemia (AML) is likely associated with elimination of the residual disease by the immune system, and possible involvement of PD-L1 in this process remains to be elucidated. We analyzed PD-L1 expression on AML primary cells by flow cytometry and, in parallel, transcript levels were determined for the transcription variants v1 and v2. The ratio of v1/v2 cDNA correlated with the surface protein amount, and high v1/v2 levels were associated with worse overall survival (p = 0.0045). The prognostic impact of PD-L1 was limited to AML with mutated nucleophosmin and concomitant internal tandem duplications in the FLT3 gene (p less than 0.0001 for this particular AML subgroup).

• Keywords
• AML, CD34, FLT3-ITD, NPM1, PD-1, PD-L1 transcript, leukemia,
• MeSH
• Leukemia, Myeloid, Acute blood   genetics   MeSH
• B7-H1 Antigen blood   genetics   metabolism   MeSH
• Nuclear Proteins genetics   MeSH
• Humans MeSH
• RNA, Messenger genetics   metabolism   MeSH
• Mutation MeSH
• Biomarkers, Tumor blood   genetics   metabolism   MeSH
• Nucleophosmin MeSH
• fms-Like Tyrosine Kinase 3 genetics   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• B7-H1 Antigen MeSH
• CD274 protein, human MeSH Browser
• FLT3 protein, human MeSH Browser
• Nuclear Proteins MeSH
• RNA, Messenger MeSH
• Biomarkers, Tumor MeSH
• NPM1 protein, human MeSH Browser
• Nucleophosmin MeSH
• fms-Like Tyrosine Kinase 3 MeSH