Somatic JAK2 mutations are the main molecular cause of the vast majority of polycythemia vera (PV) cases. According to a recent structural model, the prevalent acquired V617F mutation improves the stability of the JAK2 dimer, thereby enhancing the constitutive JAK2 kinase activity. Germline JAK2 mutations usually do not largely alter JAK2 signaling, although they may modulate the impact of V617F. We found an unusual germline JAK2 mutation L604F in homozygous form in a young PV patient, along with a low allele burden JAK2 V617F mutation, and in her apparently healthy sister. Their father with a PV-like disease had L604F in a heterozygous state, without V617F. The functional consequences of JAK2 L604Fmutation were compared with those induced by V617F in two different in vitro model systems: (i) HEK293T cells were transfected with plasmids for exogenous JAK2-GFP expression, and (ii) endogenous JAK2 modifications were introduced into HeLa cells using CRISPR/Cas9. Both mutations significantly increased JAK2 constitutive activity in transfected HEK293T cells. In the second model, JAK2 modification resulted in reduced total JAK2 protein levels. An important difference was also detected: as described previously, the effect of V617F on JAK2 kinase activity was abrogated in the absence of the aromatic residue F595. In contrast, JAK2 hyperactivation by L604F was only partially inhibited by the F595 change to alanine. We propose that the L604F mutation increases the probability of spontaneous JAK2 dimer formation, which is physiologically mediated by F595. In addition, L604F may contribute to dimer stabilization similarly to V617F.

• MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• Janus kinasa 2 genetika   MeSH
• lidé MeSH
• mutace MeSH
• zárodečné buňky * MeSH
• zárodečné mutace * MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

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.

• MeSH
• akutní myeloidní leukemie * diagnóza   genetika   MeSH
• antigeny CD274 genetika   MeSH
• biologické markery MeSH
• buněčný receptor 2 viru hepatitidy A genetika   MeSH
• DNA methyltransferasa 3A * genetika   MeSH
• lidé MeSH
• mutace MeSH
• nukleofosmin * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Deletion 20q is a recurrent abnormality in myeloid malignancies. In our previous study, we identified fusion of the additional sex combs-like 1 (ASXL1) and teashirt zinc finger homeobox 2 genes in a patient with myelodysplastic syndrome. The objective of this study was to determine the frequency of ASXL1 breakpoints in a cohort of 36 patients with deletion 20q as the sole cytogenetic aberration. A combination of molecular cytogenetic methods was used to confirm ASXL1 gene alterations in 19 of the 36 patients, and the determination of ASXL1 gene changes in patients with deletion 20q revealed clinical and prognostic impacts.

• MeSH
• chromozomální delece * MeSH
• cytogenetické vyšetření MeSH
• lidé MeSH
• lidské chromozomy, pár 20 genetika   MeSH
• myelodysplastické syndromy genetika   MeSH
• represorové proteiny genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Acute myeloid leukemia with mutated nucleophosmin (NPMc+ AML) forms a distinct AML subgroup with better prognosis which can potentially be associated with immune response against the mutated nucleophosmin (NPM). As the T-cell-mediated immunity involves antigen presentation on HLA class I molecules, we hypothesized that individuals with suitable HLA type could be less prone to develop NPMc+ AML. We compared HLA class I distribution in NPMc+ AML patient cohort (398 patients from 5 centers) with the HLA allele frequencies of the healthy population and found HLA-A*02, B*07, B*40 and C*07 underrepresented in the NPMc+ AML group. Presence of B*07 or C*07:01 antigen was associated with better survival in patients without concomitant FLT3 internal tandem duplication. Candidate NPM-derived immunopeptides were found for B*40 and B*07 using prediction software tools. Our findings suggest that a T-cell-mediated immune response could actually explain better prognosis of NPMc+ patients and provide a rationale for attempts to explore the importance of immunosuppressive mechanisms in this AML subgroup.

• MeSH
• akutní myeloidní leukemie * genetika   imunologie   mortalita   MeSH
• buněčná imunita * MeSH
• dospělí MeSH
• histokompatibilita - antigeny třídy I * genetika   imunologie   MeSH
• jaderné proteiny * genetika   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• míra přežití MeSH
• nádorové proteiny * genetika   imunologie   MeSH
• prevalence MeSH
• přežití po terapii bez příznaků nemoci MeSH
• senioři MeSH
• T-lymfocyty imunologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH

Serum samples taken at diagnosis in 28 chronic myeloid leukemia patients were tested for the presence of 20 cytokines by a magnetic bead-based Bio-plex immunoassay. According to complete cytogenetic remission achieved at 12 months of treatment, patients were divided into groups with either optimal or non-optimal outcome. Patients with increased cytokine levels tended to react optimally to the therapy more frequently than those others. TGF-β3 was a notable exception; its levels were significantly higher in patients with non-optimal outcomes. Further analysis enabled us to define two combinations of cytokine cut-off levels - namely low TGF-β3 and either high IL-8 or high MCP-1-each of which corresponded to therapy outcome better than either Sokal or EUTOS scores.

• MeSH
• biologické markery MeSH
• chronická myeloidní leukemie krev   diagnóza   mortalita   terapie   MeSH
• cytokiny krev   MeSH
• dospělí MeSH
• Kaplanův-Meierův odhad MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• prediktivní hodnota testů MeSH
• prognóza MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Nucleophosmin 1 (NPM1) mutations are frequently found in patients with acute myeloid leukemia (AML) and the newly generated sequences were suggested to induce immune response contributing to the relatively favorable outcome of patients in this AML subset. We hypothesized that if an efficient immune response against mutated nucleophosmin can be induced in vivo, the individuals expressing HLA alleles suitable for presenting NPM-derived peptides should be less prone to developing AML associated with NPM1 mutation. We thus compared HLA class I frequencies in a cohort of patients with mutated NPM1 (63 patients, NPMc+), a cohort of patients with wild-type NPM1 (94 patients, NPMwt) and in normal individuals (large datasets available from Allele Frequency Net Database). Several HLA allelic groups were found to be depleted in NPMc+ patients, but not in NPMwt compared to the normal distribution. The decrease was statistically significant for HLA B(*)07, B(*)18, and B(*)40. Furthermore, statistically significant advantage in the overall survival was found for patients with mutated NPM1 expressing at least one of the depleted allelic groups. The majority of the depleted alleles were predicted to bind potent NPM-derived immunopeptides and, importantly, these peptides were often located in the unmutated part of the protein. Our analysis suggests that individuals expressing specific HLA allelic groups are disposed to develop an efficient anti-AML immune response thanks to aberrant cytoplasmic localization of the mutated NPM protein.

• MeSH
• akutní myeloidní leukemie imunologie   MeSH
• analýza přežití MeSH
• histokompatibilita - antigeny třídy I imunologie   MeSH
• imunita * MeSH
• jaderné proteiny chemie   genetika   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• mutace genetika   MeSH
• mutantní proteiny chemie   metabolismus   MeSH
• peptidy chemie   imunologie   MeSH
• sekvence aminokyselin MeSH
• studie případů a kontrol MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In the previous paper of ours we compared, prior to start any treatment, a number of immunological parameters in 24 chronic myeloid leukemia patients with the same number of healthy subjects matched by age and sex. We found significant differences in the levels of immunoglobulins, the C4 component of complement, the C-reactive protein, interleukin 6, the composition of lymphocyte population and the production of some cytokines by stimulated CD3+ cells. Eleven of these patients were followed longitudinally. After treatment with hydroxyurea, interferon alpha, imatinib mesylate and dasatinib, or various combinations thereof, hematological remission was achieved in all patients and complete cytogenetic remission in nine of them. There was a nearly general tendency towards normalization of the abnormalities observed in the patients at their enrollment.

• MeSH
• antitumorózní látky terapeutické užití   MeSH
• C-reaktivní protein analýza   MeSH
• chronická myeloidní leukemie imunologie   terapie   MeSH
• dospělí MeSH
• hydroxymočovina terapeutické užití   MeSH
• imunoglobuliny krev   MeSH
• imunologické faktory terapeutické užití   MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• interferon alfa terapeutické užití   MeSH
• interleukin-6 krev   MeSH
• komplement analýza   MeSH
• lidé středního věku MeSH
• lidé MeSH
• longitudinální studie MeSH
• piperaziny terapeutické užití   MeSH
• přirozená imunita MeSH
• pyrimidiny terapeutické užití   MeSH
• T-lymfocyty metabolismus   MeSH
• thiazoly terapeutické užití   MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH