Significance of HLA-E and its two NKG2 receptors in development of complications after allogeneic transplantation of hematopoietic stem cells.

Transplantation of hematopoietic stem cells (HSCT) is a procedure commonly used in treatment of various haematological disorders which is associated with significantly improved survival rates. However, one of its drawbacks is the possibility of development of post-transplant complications, including acute and chronic graft-versus-host disease (GvHD) or CMV infection. Various studies suggested that NK cells and their receptors may affect the transplant outcome. In the present study, patients and donors were found to significantly differ in the distribution of the NKG2A rs7301582 genetic variants - recipients carried the C allele more often than their donors (0.975 vs 0.865, p<0.0001). Increased soluble HLA-E (sHLA-E) levels detected in recipients' serum 30 days after transplantation seemed to play a prognostic and protective role. It was observed that recipients with higher sHLA-E levels were less prone to chronic GvHD (11.65 vs 6.33 pg/mL, p=0.033) or more severe acute GvHD grades II-IV (11.07 vs 8.04 pg/mL, p=0.081). Our results also showed an unfavourable role of HLA-E donor-recipient genetic incompatibility in CMV infection development after transplantation (OR=5.92, p=0.014). Frequencies of NK cells (both CD56dim and CD56bright) expressing NKG2C were elevated in recipients who developed CMV, especially 30 and 90 days post-transplantation (p<0.03). Percentages of NKG2C+ NK cells lacking NKG2A expression were also increased in these patients. Moreover, recipients carrying a NKG2C deletion characterized with decreased frequency of NKG2C+ NK cells (p<0.05). Our study confirms the importance of NK cells in the development of post-transplant complications and highlights the effect of HLA-E and NKG2C genetic variants, sHLA-E serum concentration, as well as NKG2C surface expression on transplant outcome.

The interplay between telomeric complex members and BCR::ABL1 oncogenic tyrosine kinase in the maintenance of telomere length in chronic myeloid leukemia.

PURPOSE: Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by recurrent genetic aberration in leukemic stem cells, namely Philadelphia chromosome caused by reciprocal translocation t(9;22)(q34;q11). In our study, we analyzed the telomeric complex expression and function in the molecular pathogenesis of CML. METHODS: We employed CD34+ primary leukemic cells, comprising both leukemic stem and progenitor cell populations, isolated from peripheral blood or bone marrow of CML patients in chronic and blastic phase to analyze the telomere length and telomeric-associated proteins. RESULTS: The reduction in telomere length during disease progression was correlated with increased expression of BCR::ABL1 transcript and the dynamic changes were neither associated with the enzymatic activity of telomerase nor with gene copy number and expression of telomerase subunits. Increased expression of BCR::ABL1 was positively correlated with expression of TRF2, RAP1, TPP1, DKC1, TNKS1, and TNKS2 genes. CONCLUSIONS: The dynamics of telomere length changes in CD34+ CML cells is dependent on the expression level of BCR::ABL, which promotes the expression of certain shelterins including RAP1 and TRF2, as well as TNKS, and TNKS2, and results in telomere shortening regardless of telomerase activity. Our results may allow better understanding of the mechanisms responsible for the genomic instability of leukemic cells and CML progression.

Tracking Clonal Evolution of Multiple Myeloma Using Targeted Next-Generation DNA Sequencing.

Clonal evolution drives treatment failure in multiple myeloma (MM). Here, we used a custom 372-gene panel to track genetic changes occurring during MM progression at different stages of the disease. A tumor-only targeted next-generation DNA sequencing was performed on 69 samples sequentially collected from 30 MM patients. The MAPK/ERK pathway was mostly affected with KRAS mutated in 47% of patients. Acquisition and loss of mutations were observed in 63% and 37% of patients, respectively. Four different patterns of mutation evolution were found: branching-, mutation acquisition-, mutation loss- and a stable mutational pathway. Better response to anti-myeloma therapy was more frequently observed in patients who followed the mutation loss-compared to the mutation acquisition pathway. More than two-thirds of patients had druggable genes mutated (including cases of heavily pre-treated disease). Only 7% of patients had a stable copy number variants profile. Consequently, a redistribution in stages according to R-ISS between the first and paired samples (R-ISS″) was seen. The higher the R-ISS″, the higher the risk of MM progression and death. We provided new insights into the genetics of MM evolution, especially in heavily pre-treated patients. Additionally, we confirmed that redefining R-ISS at MM relapse is of high clinical value.

IDH2 mutations in patients with normal karyotype AML predict favorable responses to daunorubicin, cytarabine and cladribine regimen.

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) genes occur in about 20% patients with acute myeloid leukemia (AML), leading to DNA hypermethylation and epigenetic deregulation. We assessed the prognostic significance of IDH1/2 mutations (IDH1/2+) in 398 AML patients with normal karyotype (NK-AML), treated with daunorubicine + cytarabine (DA), DA + cladribine (DAC), or DA + fludarabine. IDH2 mutation was an independent favorable prognostic factor for 4-year overall survival (OS) in total NK-AML population (p = 0.03, censoring at allotransplant). We next evaluated the effect of addition of cladribine to induction regimen on the patients' outcome according to IDH1/2 mutation status. In DAC group, 4-year OS was increased in IDH2+ patients, compared to IDH-wild type group (54% vs 33%; p = 0.0087, censoring at allotransplant), while no difference was observed for DA-treated subjects. In multivariate analysis, DAC independently improved the survival of IDH2+ patients (HR = 0.6 [0.37-0.93]; p = 0.024; censored at transplant), indicating that this group specifically benefits from cladribine-containing therapy. In AML cells with R140Q or R172K IDH2 mutations, cladribine restrained mutations-related DNA hypermethylation. Altogether, DAC regimen produces better outcomes in IDH2+ NK-AML patients than DA, and this likely results from the hypomethylating activity of cladribine. Our observations warrant further investigations of induction protocols combining cladribine with IDH1/2 inhibitors in IDH2-mutant.

The impact of cytogenetic evolution and acquisition of del(17p) on the prognosis of patients with multiple myeloma.

INTRODUCTION: Prognosis of patients with newly diagnosed multiple myeloma (MM), a third most common hematological cancer, is dependent on baseline cytogenetics. However, little is known about the prognostic significance of cytogenetic evolution (CE) at the time between the diagnosis and relapse of MM. OBJECTIVES: Here, we retrospectively analyzed the prognostic impact of CE detected in a routine interphase fluorescence in situ hybridization (FISH) test in a cohort of patients with MM. PATIENTS AND METHODS: Among 650 patients evaluated with the FISH MM panel at our center between 2014 and 2019, we identified 29 individuals with MM who had been tested twice, at the time of diagnosis and relapse. Cytogenetic evolution was defined as the acquisition or loss of at least 1 cytogenetic abnormality at relapse (FISH2) compared with the baseline test result (FISH1). RESULTS: Cytogenetic evolution was seen in 14 patients (48%), whereas 15 had stable cytogenetics. Acquired chromosome 17p deletion (del[17p]) was the most common type of CE, found in 7 patients (24%). In univariable analysis, stable cytogenetics predicted longer overall survival (median not reached vs 3.8 years; hazard ratio [HR], 0.15; P = 0.04; median follow­up of 3.1 years) and longer overall survival after FISH2 (median not reached vs 0.8 years; HR, 0.13; P = 0.002; median follow­up of 0.6 years). In multivariable analysis, acquired del(17p) predicted shorter progression­free survival and the overall survival after FISH2 (HR, 9.3 and 18.8; P = 0.005 and P = 0.004, respectively). CONCLUSIONS: Presence of CE and, particularly, the acquisition of new del(17p) at relapse, negatively affect the outcome of MM. Therefore, re­evaluation of FISH at MM relapse should be included in routine clinical practice.

Correction to: Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence.

The original version of the article, "Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence" incorrectly listed the affiliation of the fourth author, Iwona Solarska. The correct affiliation is "Molecular Biology Laboratory, Institute of Hematology and Transfusion Medicine.

BCRP mRNA and FLT3-ITD are independent poor risk factors in adult patients with acute myeloid leukemia and intermediate or normal karyotype.

PURPOSE: FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is aberration associated with poor prognosis in AML. We have analyzed the expression of MDR-1, MRP-1, and BCRP mRNA in relation to FLT3-ITD in 100 AML adult patients with normal and intermediate karyotype. METHODS: The RQ-PCR method was performed to assess the expression of MDR-1, MRP-1, and BCRP mRNA, and the results were presented as coefficients calculated using an intermediate method according to Pfaffl's rule. RESULTS: According to univariate analysis, the following pretreatment variables negatively influenced disease-free survival (DFS): WBC count ≥25×109 /L (P=.037), MRP-1 mRNA ≥1.6818 (P=.028), BCRP mRNA ≥1.1892 (P=.004), FLT3-ITD (P=.005) and overall survival (OS): WBC count ≥25×109 /L (P=.031), MRP-1 mRNA ≥1.6818 (P=.01), BCRP mRNA ≥1.1892 (P=.01), FLT3-ITD (P=.001). When all prognostic variables were pooled into a multivariate model, we found that WBC count ≥25×109 /L (P=.026) and BCRP mRNA ≥1.1892 (P=.011). We observed trend in negative influence of FLT3-ITD on DFS (P=.057). BCRP mRNA ≥1.1892 (P=.035) and FLT3-ITD (P=.006) negatively, independently influenced the OS. CONCLUSIONS: The high expressions of BCRP mRNA calculated with Pfaffl's rule and FLT3-ITD are independent poor risk factors in adult patients with AML and intermediate or normal karyotype.

Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence.

PURPOSE: The Nijmegen breakage syndrome (NBS) is an inherited genetic disorder characterized by a typical facial appearance, microcephaly, growth retardation, immunodeficiency, and a strong predisposition to malignancies, especially of lymphoid origin. NBS patients have a mutation in the NBN gene which involves the repair of DNA double-strand breaks (DSBs). Here we studied the peripheral T cell compartment of NBS patients with a focus on immunological senescence. METHODS: The absolute numbers and frequencies of the different T cell subsets were determined in NBS patients from young age till adulthood and compared to age-matched healthy individuals (HI). In addition, we determined the expression of senescent T cell markers and the signal joint T cell receptor excision circles (sjTRECs) content. RESULTS: Our results demonstrate that NBS patients have reduced T cell numbers. NBS patients showed lower numbers of αß+ T cells, but normal γδ+ T cell numbers compared to HI. Concerning the αß+ T cells, both CD4+ as well as CD8+ T cells were excessively reduced in numbers compared to aged-matched HI. In addition, NBS patients showed higher frequencies of the more differentiated T cells expressing the senescent cell marker CD57 and did not express co-stimulatory molecule CD28. These effects were already present in the youngest age group. Furthermore, NBS patients showed lower sjTREC content in their T cells possibly indicative of a lower thymic output. CONCLUSIONS: We conclude that circulating T cells from NBS patients show signs of a senescent phenotype which is already present from young age on and which might explain their T cell immune deficiency.

Mild chronic graft-versus-host disease may alleviate poor prognosis associated with FLT3 internal tandem duplication for adult acute myeloid leukemia following allogeneic stem cell transplantation with myeloablative conditioning in first complete remission: a retrospective study.

Internal tandem duplication (ITD) of the FLT3 gene (Fms-like tyrosine kinase 3) is the most commonly found mutation in acute myeloid leukemia (AML). The significance of FLT3-ITD at diagnosis was retrospectively estimated for allo-HSCT (allogeneic hematopoietic stem cell transplantation) outcomes in 140 patients, median age of 38, undergoing allo-HSCT after myeloablative conditioning in first complete remission of AML. FLT3-ITD was detected at AML diagnosis in 42/140 (30%) of included into this study patients. At 3 years, relapse incidence (RI) following allo-HSCT in AML patients with intermediate or normal karyotype was significantly higher in those FLT3-ITD positive than FLT3-ITD negative [52.9 vs. 20.4%, P = 0.002]. Additionally, patients with mild chronic graft-versus-host disease (cGvHD) had significantly lower RI compared to patients with moderate or severe grade cGvHD or those not experiencing cGvHD, respectively, 4.8 vs. 36.0 vs. 27.8%, P = 0.032. FLT3-ITD was harboring a poor prognosis in AML with intermediate or normal karyotype and significantly increased risk of relapse following allo-HSCT. It appears that allo-HSCT does not cure patients with FLT3-ITD, unless they develop symptoms of mild cGvHD and graft versus leukemia, which may decrease RI.

CEBPA copy number variations in normal karyotype acute myeloid leukemia: Possible role of breakpoint-associated microhomology and chromatin status in CEBPA mutagenesis.

Copy number variations (CNV) in CEBPA locus represent heterogeneous group of mutations accompanying acute myeloid leukemia (AML). The aim of this study was to characterize different CEBPA mutation categories in regard to biological data like age, cytology, CD7, and molecular markers, and identify possible factors affecting their etiology. We report here the incidence of 12.6% of CEBPA mutants in the population of 262 normal karyotype AML (NK-AML) patients. We confirmed that double mutant AMLs presented uniform biological features when compared to single CEBPA mutations and accompanied mostly younger patients. We hypothesized that pathogenesis of distinct CEBPA mutation categories might be influenced by different factors. The detailed sequence analysis revealed frequent breakpoint-associated microhomologies of 2 to 12bp. The analysis of distribution of microhomology motifs along CEBPA gene showed that longer stretches of microhomology at the mutational junctions were relatively rare by chance which suggests their functional role in the CEBPA mutagenesis. Additionally, accurate quantification of CEBPA transcript levels showed that double CEBPA mutations correlated with high-level CEBPA expression, whereas single N-terminal CEBPA mutations were associated with low-level CEBPA expression. This might suggest that high-level CEBPA expression and/or accessibility of CEBPA locus contribute to B-ZIP in-frame duplications.

FLT3-ITD and MLL-PTD influence the expression of MDR-1, MRP-1, and BCRP mRNA but not LRP mRNA assessed with RQ-PCR method in adult acute myeloid leukemia.

Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) and mixed-lineage leukemia gene-partial tandem duplication (MLL-PTD) are aberrations associated with leukemia which indicate unsatisfactory prognosis. Downstream regulatory targets of FLT3-ITD and MLL-PTD are not well defined. We have analyzed the expression of MDR-1, multidrug resistant protein-1 (MRP-1), breast cancer resistance protein (BCRP), and lung resistance protein (LRP) messenger RNA (mRNA) in relation to the mutational status of FLT3-ITD and MLL-PTD in 185 acute myeloid leukemia (AML) adult patients. The real-time quantitative polymerase chain reaction method was performed to assess the expression of the MDR-1, MRP-1, BCRP, and LRP mRNA, and the results were presented as coefficients calculated using an intermediate method according to Pfaffl's rule. Significantly higher expressions of MDR-1 mRNA were found in patients who did not harbor FLT3-ITD (0.20 vs. 0.05; p = 0.0001) and MRP-1 mRNA in patients with this mutation (0.96 vs. 0.70; p = 0.002) and of BCRP mRNA in patients with MLL-PTD (0.61 vs. 0.38; p = 0.03). In univariate analysis, the high expression of MDR-1 mRNA (≥0.1317) negatively influenced the outcome of induction therapy (p = 0.05), whereas the high expression of BCRP mRNA (≥1.1487) was associated with a high relapse rate (RR) (p = 0.013). We found that the high expression of MDR-1 (≥0.1317), MRP-1 (≥0.8409), and BCRP mRNA (≥1.1487) significantly influenced disease-free survival (DFS; p = 0.059, 0.032, and 0.009, respectively) and overall survival (0.048, 0.014, and 0.059, respectively). Moreover, a high expression of BCRP mRNA (≥1.1487) proved to be an independent prognostic factor for RR (p = 0.01) and DFS (p = 0.002) in multivariate analysis. The significant correlation between the expression of MDR-1, MRP-1, and BCRP mRNA and FLT3-ITD or MLL-PTD in AML patients requires further investigation.

[Standardization of quantitative detection of BCR-ABL gene expression by RQ-PCR in patients with chronic myeloid leukemia in cooperation with European Leukemia Net]. / Standaryzacja ilosciowej oceny ekspresji genu BCR-ABL metoda RQ-PCR u chorych na przewlekla bialaczke szpikowa we wspólpracy z European Leukemia Net.

Monitoring of chronic myeloid leukemia treatment efficacy requires very sensitive methods of BCR-ABL gene detection based on polymerase chain reaction (PCR). The lack of comparability of BCR-ABL mRNA quantification results generated by various methodologies in different laboratories was the cause of an international multicenter trial initiation with the participation of 133 laboratories in 24 European countries cooperating within the "EUTOS for CML" project. Pracownia Diagnostyki Molekularnej Kliniki Hematologii is taking part in standardisation rounds organised since 2005. The compatibility of methodology used in Pracownia with European Leukemia Net (ELN) standards was confirmed, and correction factor for the expression of RQ-PCR results in an international scale was calculated. Pracownia was charge by ELN with a task of conducting the standardisation in polish molecular biology laboratories. Test probes were prepared and sent to eight cooperating laboratories. The results obtained in six laboratories were concordant with results from laboratory in Krakow after conversion to international scale, therefore it was possible to calculate individual correction factors. The participation of polish laboratories in international standardization process created the opportunity for unification of BCR-ABL quantification methodologies with recommendations of international experts, and showed that the quality of analyses performed in majority of them was satisfactory enough to calculate correction factor and to express the RQ-PCR results in widely accepted international scale.

Frequency of BCR-ABL gene mutations in Polish patients with chronic myeloid leukemia treated with imatinib: a final report of the MAPTEST study.

INTRODUCTION: The presence of BCR-ABL oncogene mutations in patients with chronic myeloid leukemia (CML) may be responsible for the failure of tyrosine kinase inhibitor treatment. OBJECTIVES: The aim of the study was to evaluate the frequency of BCR-ABL gene mutations in patients with CML (the MAPTEST study) treated with imatinib (IM). PATIENTS AND METHODS: Direct sequencing analysis of BCR-ABL gene was performed in 92 patients treated with IM for more than 3 months. The mean time of IM treatment was 18 months. At the time of the analysis, 75 patients were in the first chronic phase (CP), 4 in the second CP, 5 in the acceleration and 8 in the blastic phase. Fifty-seven patients (62%) were treated with IM at a daily dose of 400 mg and 35 patients with higher doses (600 or 800 mg daily). Inclusion criteria were based on the European Leukemia Net definitions for failure and suboptimal response to IM. RESULTS: Twelve mutations were detected in 11 of 92 patients, including 4 mutations (36.7%) diagnosed during CP, 3 (27.3%) in acceleration, and 4 (36.7%) in blast crisis. In 1 patient with lymphoid blast crisis of CML coexisting F359V and Y253F mutations were detected. In the whole group mutations were detected in 2 of 5 patients (40%) with primary resistance (M351T, F359V + Y253F) and in 9 of 87 patients (10.3%) (E255K, T315I-3x, M351T, E355G, F359V-2x) with acquired resistance to IM. CONCLUSIONS: The study confirmed the usefulness of BCR-ABL gene mutation screening in patients with CML resistant to IM therapy.

Complete cytogenetic and molecular response after imatinib treatment for chronic myeloid leukemia in a patient with atypical karyotype and BCR-ABL b2a3 transcript.

The molecular hallmark of CML is the BCR-ABL fusion gene, usually with specific breakpoints within ABL intron 1 and BCR introns b2, b3, and e19. The amplification of the BCR-ABL hybrid gene resulting from additional copies of the Ph chromosome has been identified as a mechanism for imatinib (IM) resistance. Cytogenetic clonal evolution correlates with the accelerated phase of leukemia, whereas deletions in the derivative chromosome 9 are associated with a poor prognosis. Relevance in IM therapy is unclear. We report a case of a 39-year-old male with chronic phase CML. Cytogenetic studies showed a complex karyotype with additional copies of the Ph chromosome, sextasomy 8, and ASS gene deletion. An unusual aberrant fusion gene product was derived from the joining of BCR exon 13 (b2) and ABL exon 3 (a3). During IM treatment, the patient was monitored in 3- to 6-month intervals. Major cytogenetic response was achieved after 5 months; complete cytogenetic and molecular remission was reached after 8 months; after 22 months, normal karyotype and absence of the BCR-ABL product continued. Our data seem to confirm the data of others in regards to the b2a3 breakpoint, suggesting a better prognosis, regardless of other unfavorable factors.