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Background. Acquired aplastic anemia (AA) is a non-tumor disease of the blood system and the pathogenesis is based on immune dysregulation directed against own hematopoietic stem cells, which leads to the development of bone marrow aplasia. Some modern research is directed to the study of intrinsic defects of hematopoietic stem cells, and one of which is the change in telomere length. Several large studies have shown the association of telomere shortening in AA patients with decreased overall survival, poor response to immunosuppressive therapy (IST), high rates of relapse and clonal complications.Aim. To study the influence of the initial telomeric DNA regions length in AA patients on the disease course.Materials and methods. 43 adult patients with acquired AA without previous pathogenetic therapy were included in the study. IST was performed according to a standard protocol including the use of hATG and cyclosporine. Flow-FISH was used as the method for measuring relative telomere length, and peripheral blood mononuclear cells were used as the study material.Results. Telomere length determined before IST did not differ between non-severe and severe AA, but there were significant differences depending on disease duration (p = 0.032). Initially short telomeres correlated with a lower rate of achieving hematologic improvement (53 % vs. 80 %; p = 0.059). In addition, significantly worse results were obtained in achieving partial and complete remission in patients with initially short telomeres compared to those with initially long telomeres (37 % vs. 62 % and 5 % vs. 23 %, respectively; p

Background. Aplastic anemia (AA) is a non-tumor and rare disease of the blood system, characterized by deep pancytopenia due to the development of bone marrow aplasia with immune-mediated damage of hematopoietic stem cells. Research results indicate the presence of antigenic effects leading to pathological activation and dysregulation of the T cells in the bone marrow with increased production of pro-inflammatory cytokines that damage hematopoietic stem cells. The triggering factor that initiates the cascade of immune reactions is currently unknown. The high efficiency of immunosuppressive therapy (IST), which allows achieving remission in the majority of AA patients, is evidence of the immune genesis of the disease. The pathogenesis of AA is currently being actively studied. The participation of T cell subpopulations in immune response is beyond doubt, but the issues of their significance in the AA pathogenesis have not been fully studied. A more detailed understanding of the AA development mechanisms is necessary for the development of long-term effective treatment.Aim. To investigate the T cells subpopulation in bone marrow of AA patients during IST.Materials and methods. The study included 41 patients over 18 years of age with newly diagnosed acquired AA without previous IST. Treatment was carried out according to a protocol including horse antithymocyte globulin and cyclosporine. Flow cytometry was used to detect T cell subpopulations. Bone marrow examination was performed at three time points: initially, 3 and 6 months after initiation of combined IST.Results. Multidirectional changes in the T cell subpopulations ratio before the start of IST were found in all AA patients included in the prospective study: most patients had a higher proportion of effector CD4+ and CD8+ T cells (61 and 83 % of patients, respectively), memory CD4+ T cells (63 % of patients), and a lower proportion of naive CD4+ and CD8+ T cells (81 and 51 % of patients, respectively) compared to donors (p

Background. Differentiation syndrome (DS) is a potentially fatal complication of therapy for acute promyelocytic leukemia (APL) with an incidence of up to 48 %. To date, no reliable DS risk factors have been found, with the exception of leukocytosis at the APL onset.Aim. To determine the risk factors associated with DS in patients with APL during induction therapy with arsenic trioxide (ATO) and tretinoin (ATRA).Materials and methods. The study included 39 patients with APL, 29 (74.4 %) of them were classified as low-risk according to ELN (European Leukemia Net), 10 (25.6 %) were classified as high-risk. At the disease onset, cytological and molecular (chimeric transcript PML::RARα, FLT3-ITD mutation) bone marrow studies were performed, the expression of 28 differentiation antigens by blood and bone marrow blast cells was determined (markers of early precursors, myeloid and lymphoid differentiation, cell adhesion molecules, chemokine receptors, integrins, selectin), body mass index (BMI) and the leukocytes number dynamics during induction course were assessed. All patients received ATRA and ATO therapy. Patients from the high-risk group at the onset received 1–3 injections of idarubicin (12 mg/m2) and dexamethasone (8–10 mg/m2 2 times a day) to prevent DS until leukocytosis reduced. In cases of DS, dexamethasone was prescribed at a dose of 10 mg/m2 2 times a day; in cases of severe DS, the induction course was interrupted.Results. Of the 39 patients, 12 (30.8 %) were diagnosed with DS: 20 % of high-risk patients (2/10) and 34.5 % of low-risk patients (10/29). There was no statistically significant association of leukocytosis more than 10 × 109 /L at onset, microgranular morphology of blast cells, bcr3-variant PML::RARα, FLT3-ITD mutation with DS. In multivariate analysis, the probability of DS was associated with BMI ≥30 kg/m2 and mean fluorescence intensity of CD38 antigen by blast cells, regardless of risk group. based on the results of the ROC-analysis, the threshold value of mean CD38 fluorescence intensity was set at 25,000 cu, if exceeded, DS is highly likely to develop.Conclusion. the high incidence of DS among low-risk patients is probably due to the lack of prophylactic glucocorticosteroids administration for the development of leukocytosis during ATRA and ATO therapy. BMI ≥30 kg/m2 and mean CD38 fluorescence intensity more than 25,000 cu were identified as statistically significant DS risk factors.

Background. Aplastic anemia proceeds with bone marrow failure and is associated with immunological suppression of normal blood stem cells’ proliferation, which lead to bone marrow aplasia. autoimmune aggression and internal defects of blood stem cell that cause abnormal hematopoiesis are being actively studied. An important role in the pathogenesis of the aplastic anemia is played by instability of telomere length (TL). determination of the initial TL makes it possible to clearly differentiate between the aplastic anemia and dyskeratosis congenita. also, it helps to identify the group of patients with short telomeres for prediction of therapy response. Aim. To investigation the TL of various blood and bone marrow cells in patients with aplastic anemia before treatment. Materials and methods. The group of patients with aplastic anemia was investigated (n = 45). blood donors (n = 32) and bone marrow donors (n = 10) of different ages were included in the reference group. adult patients with dyskeratosis congenita (n = 5) were included in the comparison group. Relative and absolute tl was identified in peripheral blood and bone marrow mononuclear cells, monocytes, lymphocytes by flow-FISH technique (combination of flow cytometry and fluorescence in situ hybridization). Results. Relative and absolute TL was comparable in different blood and bone marrow cells in patients with aplastic anemia before treatment. TL in peripheral blood and bone marrow mononuclear cells wasn’t significantly differed in groups of patients with aplastic anemia and healthy donors. Telomeres in patients with dyskeratosis congenita were identified as “ultrashort” and were significantly shorter than in patients with aplastic anemia. Conclusion. Determination of TL in patients with aplastic anemia is modern examination method, which is a necessary step of differential diagnosis between aplastic anemia and dyskeratosis congenita, which is the disease from group of constitutional bone marrow aplasia. It is preferred to identify the TL in adult patients with aplastic anemia by the flow-FISH. It is necessary to investigate the TL to predict treatment response and to identify risks of developing adverse experiences, which include relapse and clonal evolution.

Background. The effectiveness of therapy for acute T-lymphoblastic leukemia (T-ALL) and T-lymphoblastic lymphoma (T-LBL) has significantly improved over the past decades, including through the implementation of hematopoietic stem cell transplantation (HSCT). The Russian multicenter ALL-2009 study (ClinicalTrials.gov NCT01193933) showed that performing autologous HSCT (auto-HSCT) in patients with T-ALL/LBL improves long-term results. However, the study was non-randomized and the need for auto-HSCT in clinical practice requires careful study.Aim. To assess the significance of auto-HSCT in patients with T-ALL/LBL in the framework of ALL-2016 multicenter, prospective, randomized study (ClinicalTrials.gov NCT03462095).Materials and methods. The study included 109 adult patients with T-ALL/LBL (m:f 82:27). Median age was 31 (18– 52) years. T-ALL was diagnosed in 88 (81 %) patients, T-LBL in 21 (19 %) patients. All patients are treated according to the ALL-2016 protocol. Using the web platform, upon completion of induction therapy (+70 days), all T-ALL/LBL patients who achieved clinical and hematological remission were randomized to the auto-HSCT arm or chemotherapy alone (CT). Centralized monitoring of minimal residual disease (MRD) in bone marrow samples was performed by multicolor flow cytometry at the control points according to the ALL-2016 protocol. Statistical analysis was performed using SAS 9.4.Results. 87 patients with T-ALL/LBL were randomized: 44 to the auto-HSCT arm and 43 to the CT arm. Further analysis included 25 patients who underwent auto-HSCT and 36 patients receiving only CT. Three-year relapse-free survival in T-ALL is estimated at 62 % (auto-HSCT) vs. 81 % (CT) (p = 0.3422), and in T-LBL – 67 % (auto-HSCT) vs. 79 % (CT) (p = 0.59). MRD persistence on the +70th day of therapy according to the ALL-2016 protocol was determined in 40 % of patients (autoHSCT) and in 67 % (CT) (p = 0.057). In a multivariate analysis, it was determined that T-ALL from early T-cell precursor (ETP-variant) and MRD persistence after the end of II phase induction are the main risk factors for relapse in the treatment according to the ALL-2016 protocol.Conclusion. Performing auto-HSCT both in patients with T-ALL and T-LBL, and with MRD persistence on day +70 according to the ALL-2016 protocol did not improve long-term results. The development of new programs for the treatment of patients with MRD persistence, as well as the ETP variant of T-ALL, is of current interest.

The graft-versus-host disease (GVHD) is among the most common complications after hematopoietic stem cell transplantation (allo-HSCT). The main tools for GVHD prevention remain calcineurin inhibitors (cyclosporin A, tacrolimus), methotrexate, mycophenolate mofetil. Upon implementation of reduced-intensity conditioning regimens, antithymocyte globulin was widely introduced. However, negative effects upon reconstitution of T-cell immunity have been noted, thus increasing risk of severe infectious complications and disease relapse. With extended practice of HSCT from alternative (partially matched or haploidentical) donors, cyclophosphamide was increasingly used. Our aim was to study reconstitution of immune cell subpopulations in the patients undergoing bone marrow transplantation (BMT), when using different GVHD prophylaxis regimens, including the schedules with post-transplant CP usage. The study concerned 44 cases classified into 2 groups. The first one included patients with standard immunosuppressive therapy, antithymocyte therapy, cyclosporine A, methotrexate, mycophenolate mofetil. The second group included the patients who received CP as immunosuppressive drug combined with other treatments (cyclosporine A, methotrexate, mycophenolate mofetil). At specified control terms, (D+14, +30, +60, +90) the blood leukocyte subpopulations were assayed by means of multicolor flow cytometry. Absolute counts of CD4+ cells in HSCT recipients treated with CP post-BMT proved to be sufficiently lower at D+14 and +30, than in those treated with classical immunosuppressive therapy. However, at later terms, (D+60, +90), these differences were not observed. Moreover, in CP-treated bone marrow recipients, absolute numbers of CD8+ cells was significantly higher, compared to the patients who received conventional GVHD prophylaxis. Reconstitution of the studied lymphocyte populations in hematopoietic cell recipients did not depend on the GVHD prophylaxis regimen. Usage of CP combined with bone marrow as a source of stem cells, brings about sufficient decrease of some cell populations (CD4+; CD8+; NK cells) at early terms post-transplant. Administration of CP combined with hematopoietic stem cells as the source of hematopoietic graft seems to be more reasonable.

Background. Splenic marginal zone lymphoma (SMZL) is an indolent non-Hodgkin’s B-cell lymphoma. It presents morphologically by mature lymphoid B-cells. They conform to these immunological characteristics of marginal zone lymphocytes from secondary follicles. The tumor B-cells of SMZL do not have specific markers of immunophenotype and requires the exclusion of other non-Hodgkin’s B-cell lymphomas. There is an annual increase in the incidence of SMZL. There are refractory forms and progressive course of the SMZL. There is a huge variety of the mechanisms of evading tumor cells from immunological control. Unlike solid tumors, B-lymphoproliferative diseases are characterized by the expression of HLA I/II and co-stimulatory molecules (CD80 and CD86). Therefore, tumor B-lymphocytes can act as antigen-presenting cells (APC) for T lymphocytes. The T-cell immune response is known to play an important role in antitumor control. It is known that effective activation of T-lymphocytes requires the formation of an immunological synapse and the presence of two activation signals (antigen recognition and co-stimulation of CD28-CD80/86). According to the modern concept of tumor development, there is a gradual selection of tumor clones. As a result, only tumor cells that are invisible to the immune system remain. Mechanisms of evasion of tumor B-cells of SMZL from immune surveillance are currently not fully understood and are being actively studied.Objective: to study the expression features of antigens involved in the formation of immunological synapse in patients with SMZL in peripheral blood.Materials and methods. The study includes 10 primary SMZL patients; all patients have stage IV according to the Ann Arbor classification. Splenectomy was performed for all patients as a first stage of treatment. Two patients had progression of SMZL after splenectomy, which required chemotherapy. The control group included 25 healthy donors. Peripheral blood was used as a material for analysis. The study was conducted on a 6-color BD FACS Canto II flow cytometer (BD Biosciences, USA) immediately after diagnosis.Results. Tumor B-cells of SMZL are different from B-cells of healthy donors with a greater proportion of CD80+, FAS+, PD-1+-cells, which may correspond to activated B-cells. The proportion of CD4+PD-1+ and CD8+PD-1+ T-cells in patients with SMZL was higher in comparison with the control group. There was a large proportion of T-cells expressing PD-1 in the group of patients with SMZL progression after splenectomy in comparison with the group of patients with indolent course of SMZL. Conclusion. Thereby, tumor B-cells of the SMZL retains the features of non-tumor analogues. The most significant mechanism for evading immune surveillance in an SMZL is inhibition of the T-cell immunity via the PD-1–PD-L1 pathway. The most pronounced inhibition of T-cell immunity causes an uncontrolled tumor process.

Aim.Analysis of the effectiveness of the MSCs aministration as the second- or third-line therapy of acute GVHD (aGVHD) resistant to glucocorticosteroid treatment. Materials and methods.The study included 35 patients who received MSCs obtained from the bone marrow of healthy donors as a treatment of steroid-resistant aGVHD. The clinical parameters of patients, MSCs cultural characteristics, the MSC expression profile for various genes including those involved in immunomodulation, expression of cells surface markers, the source of MSCs, as well as the frequency and number of MSC administrations were analyzed. Results.Response to therapy was achieved in 74% of cases, a complete response was reached in 13 (37%) patients, partial response/clinical improvement was demonstrated in 13 (37%). This treatment was ineffective in 9 patients. The prediction of a group of patients with good response to MSC therapy turned to be impossible. The differences between the effective and ineffective for the GVHD treatment MSCs samples were found. The effective ones were characterized with a decreased total MSCs production and an increase in the main histocompatibility complex and PDL-1 antigens expression. Conclusion.These data allow to select optimal samples for aGVHD treatment that can improve clinical results. aGVHD treatment with MSCs has shown efficacy comparable to other treatment approaches. Given the low percentage of complications and the absence of significant adverse effects, MSC therapy seems to be one of the optimal approaches to the treatment of resistant forms of GVHD.

The study objective is to investigate the features of subpopulational composition of mobilized hematopoietic stem cells in peripheral blood (PB) and leukocyte concentrates (LC) in adult patients with oncohematological pathology and donors.Materials and methods. In 80 patients with hemoblastoses, expression of CD38, HLA-DR and CD143 (angiotensin-converting enzyme) was measured in PB and LC CD34+CD45low cells. The control group included 10 PB and 14 LC samples from healthy donors. Analysis of PB was performed prior to mobilization of hematopoietic stem cells (HSC) and on the day of leukapheresis prior to HSC collection. LC samples were examined at day 1 after HSC collection.Results. CD143 is expressed on CD34+CD45low cells both prior to mobilization and after it in all patients and donors, but CD34+CD45lowCD143+ cell counts varied depending on diagnosis and mobilization regimen. CD143+ expression on CD34+CD45low cells was significantly higher in patients who received combination of chemotherapy and granulocyte colony-stimulating factor compared to donors and patients with multiple myeloma who received only granulocyte colony-stimulating factor. Along with elevated CD34+CD45low cell count after hematopoiesis stimulation, CD34+CD45lowCD143+ cell counts also increased. It was shown that mobilized HSC almost completely lacks a fraction of early CD34+CD45low progenitor cells not expressing CD38, HLA-DR. Prior to hematopoiesis stimulation among CD34+CD45low cells, CD38+HLADR–cell fractions are prevalent, but after mobilization CD38–HLA-DR+ cell counts increased. No differences between CD34+CD45lowCD143+cell counts in patients with multiple myeloma depending on disease status, sex, age or number of chemotherapy courses prior to HSC mobilizationwere observed.Conclusion. Expression of angiotensin-converting enzyme on CD34+ cells in PB before and after HSC mobilization and in LC was observed. The cell counts varied depending on diagnosis and mobilization regimen.

Background. Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disease that manifests by the accumulation of tumor monoclonal B-lymphocytes in the bone marrow, peripheral blood and secondary lymphoid organs. Recently it was found that CLL cells are able to form immunological synapses with microenvironment cells, directly and indirectly affecting their function. Therefore, it became clear that the pathogenesis of CLL is not only escape of apoptosis but also the ability of CLL cells to cause T-lymphocyte anergy, thereby avoiding immune surveillance.Objective: to study the expression of FAS, co-stimulatory molecules CD80 and CD86, PD-1, PD-L1 on CLL cells, and also to study the basic subpopulations of T-cells (naїve, memory, effector cells).Materials and methods. The study included 46 CLL patients: 16 patients with disease progression after chemotherapy and 30 patients with newly diagnosed CLL. “Primary” patients are categorized according to J. Binet’s CLL stages. Stage A was established in 14 patients, B – 10, C – 6. The control group included 29 healthy donors. Peripheral blood was used as a material for analysis. The study was performed on a 6-color flow cytometer BD FACS Canto II (BD Biosciences, USA).Results. In CLL patients, the proportion of CD80+, CD86+, FAS+ B-cells was significantly lower than in donors. In “primary” patients the proportion of CD80 + CLL cells was higher than in patients with CLL progression. Among “primary” patients the proportion of CD80+ and CD86+ was lower in advanced stages of the disease. In patients with CLL progression the proportion of FAS+ B cells was higher than in “primary” patients. The proportion of PD-1+ B cells in CLL patients was higher than in donors and “primary” patients. The proportion of PD-1+ tumor cells was significantly lower in advanced stages of the disease. The proportion of PD-L1+ B cells in CLL patients was lower than in donors. Among the “primary” patients, the proportion of PD-L1+ B-lymphocytes was higher in stage A. The proportion of PD-1+ Thelpers was higher in CLL patients than in donors, and among “primary” patients it was higher in advanced stages of the disease. The proportion of PDL1+ T-helpers and cytotoxic T-cells in CLL patients was lower than in donors. The proportion of naїve cells (CD95-CD28+) in patients compared with donors was lower and the proportion of effector cells (CD95+ CD28–), memory cells (CD95 + CD28 +) was higher, a proportion of CD8+ memory T-cells was higher among patients in the advanced stage of CLL.Conclusion. Therefore, a decline the CD80/CD86+ B-cells in CLL can cause ineffectiveness of an immunological synapse between tumor cells and T-cells, which leads to anergy of T-lymphocytes. Decline expression of the FAS receptor allows tumor CLL cells to avoid FAS-mediated apoptosis. A change in the T-cell pool toward memory cells and effectors, the acquisition of a CD4+PD-1+ (“exhausted”) phenotype impaired antitumor immunity and possible leads to disease progression.

Myelodysplastic syndromes (MDS) are heterogeneous group of clonal hematological neoplasms characterized by cytopenias, sighs of dysplasia and high risk of transformation in acute myeloid leukemia. Diagnostics of MDS requires a comprehensive approach, but even when performing cytological, cytogenetic, molecular and histological studies, it is not always possible to establish a diagnosis. Multicolor flow cytometry (MFC) is a high-tech method, increasingly used in the diagnosis of various hematologic diseases. Over the last years, MFC is standardized for assessing of dysplasia in all cell compartments of the bone marrow. Many research groups have demonstrated high sensitivity and specificity of this diagnostic approach, which indicates the necessity of integration of flow cytometric study into diagnostic protocols of MDS.