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Introduction. One of the main causes of treatment failure after allogeneic hematopoietic stem cells transplantation (alloHSCT) for acute leukemia (AL) is disease relapse. In recent years, multiparameter fl ow cytometry (MPC) has been widely used to detect minimal residual disease (MRD) because of its capacity to identify patients with a high risk of relapse due to availability and the ability to obtain results in a timely manner.Aim — to evaluate the prognostic value of MRD status before allo-HSCT and the effect of donor type and conditioning intensity on long-term results of allo-HSCT of MOB-positive patients.Patients and methods. The analysis included 107 patients with acute myeloid leukemia (AML) and 63 patients with acute lymphoblastic leukemia (ALL) who underwent allo-HSCT between September 2015 and June 2020. All patients were in complete morphological remission before allo-HSCT. At the time of allo-HSCT 91 patients with AML and 37 patients with ALL were in the first complete remission (CR), in their second and more than two CRs were 16 and 26 patients, respectively. The median follow-up was 18 (1.5–48) months for AML and 14 (1.8–60.1) months for ALL. Immunophenotypic study was performed before allo-HSCT. MRD was detected using a combination of the “different from normal” method and the search for cells with a leukemia-associated immunophenotype.Results. The disease status at the time of transplantation and the presence of MRD before allo-HSCT were independent factors infl uencing the probability of relapse (disease status: HR = 2.911, 95% CI: 1.328–6.379; MRD before allo-HSCT: HR = 7.667, 95% CI: 3.606–16.304) and post-transplant mortality (disease status: HR = 2.911, 95% CI: 1.328–6.379; MRD before allo-HSCT: HR = 7.667, 95% CI: 3.606–16.304). In univariate analysis, the relapse-free survival of MRD+ patients with AL in the first CR was significantly worse than in MRD– (AML: 23 % versus 57 %, p < 0.0001, ALL: 34 % versus 61.7 %, p = 0.0484), and the probability of relapse in MRD+ patients was significantly higher (AML: 75 % versus 12 %, p < 0.0001, ALL: 57 % versus 7 %, p = 0.0072). Pre-transplant MRD status was not prognostically significant for AL-patients in the second and third remission. The development of chronic GVHD reduces post-transplant mortality if it does not require systemic therapy with glucocorticosteroids (HR = 0.006, 95% CI: 0.008–0.446).Conclusion. Testing for MRD of patients with AL in the first CR before allo-HSCT is necessary for risk stratification and identification of patients who will need preventive post-transplant therapy in order to prevent disease relapse.

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.

The study objectiveis 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.

To identify a parameter predicting a collection of at least 2·106 CD34+ hematopoietic stem cells (HSC)/kg body weight per leukapheresis (LA) procedure.The investigation included 189 patients with hematological malignancies and 3 HSC donors, who underwent mobilization of stem cells with their subsequent collection by LA. Absolute numbers of peripheral blood leukocytes and CD34+ cells before a LA procedure, as well as a number of CD34+ cells/kg body weight (BW) in the LA product stored on the same day were determined in each patient (donor).There was no correlation between the number of leukocytes and that of stored CD34+ cells/kg BW. There was a close correlation between the count of peripheral blood CD34+ cells prior to LA and that of collected CD34+ cells calculated with reference to kg BW.The optimal absolute blood CD34+ cell count was estimated to 20 per µl, at which a LA procedure makes it possible to collect 2·106 or more CD34+ cells/kg BW.Цель исследования. Выявление параметра, прогнозирующего сбор не менее 2·106 гемопоэтических стволовых клеток (ГСК) CD34+ на 1 кг массы тела (МТ) пациента за одну процедуру лейкафереза (ЛА). Материалы и методы. В исследование включили 189 пациентов с онкогематологическими заболеваниями и 3 доноров ГСК, которым проведена мобилизация стволовых клеток с последующим их сбором методом ЛА. У каждого пациента (донора) определяли абсолютное количество лейкоцитов и клеток CD34+ в периферической крови перед процедурой ЛА, а также количество клеток CD34+ на 1 кг МТ пациента в продукте ЛА, заготовленного в этот же день. Результаты. Корреляции между количеством лейкоцитов в крови и количеством заготовленных в продукте ЛА клеток CD34+ на 1 кг МТ не выявлено. Выявлена тесная корреляция между количеством клеток CD34+ в периферической крови до ЛА с количеством собранных ГСК, рассчитанных на МТ пациента. Заключение. Определено оптимальное абсолютное число клеток CD34+ в крови - 20 в 1 мкл, при котором за один ЛА возможно собрать 2·106 и более клеток CD34+ на 1 кг МТ.

In diffuse large B-cell lymphoma, bone marrow involvement is rarely diagnosed. We compared the properties of bone marrow stromal progenitor cells and the concentration of fibroblast CFU in patients with diffuse large B-cell lymphoma without bone marrow involvement and in healthy donors. It was found that the properties of multipotent mesenchymal stromal cells in patients in the debut of the disease differed considerably from those in healthy donors. In particular, the total cell production in patients was significantly higher than in donors. In multipotent mesenchymal stromal cells of patients, some cell parameters were changes; the mean fluorescence intensity of the adhesion molecule ICAM1 on the cell surface was increased. The mean fluorescence intensity of mesenchymal stromal cell markers (HLA-ABC, CD73 and CD90) was significantly elevated. The relative expression of BMP4, MMP2, FGFR1, and ICAM1 genes in mesenchymal stromal cell was reduced, while the expression of FGFR2 gene was enhanced. Despite the absence of proven involvement of the bone marrow, the properties of mesenchymal stromal cells, the components in the stromal microenvironment niche regulating hemopoiesis are altered in patients with diffuse large B-cell lymphoma.

To determine the efficiency of maintenance therapy with bortezomib in patients with multiple myeloma (MM) who have achieved complete remission (CR) after autologous hematopoietic stem cell (auto-HSCT), depending on the presence of minimal residual disease (MRD).In January 2014 to February 2016, fifty-two MM patients (19 men and 33 women) aged 24 to 66 years (median 54 years), who had achieved CR after auto-HSCT, were randomized to perform maintenance therapy with bortezomib during a year. On day 100 after auto-HSCT, all the patients underwent immunophenotyping of bone marrow plasma cells by 6-color flow cytometry to detect MRD. Relapse-free survival (RFS) was chosen as a criterion for evaluating the efficiency of maintenance therapy.After auto-HSCT, MRD-negative patients had a statistically significantly higher 2-year RFS rate than MRD-positive patients: 52.9% (95% confidence interval (CI), 35.5 to 70.5%) versus 37.2% (95% CI, 25.4 to 49.3%) (p=0.05). The presence of MRD statistically significantly increased the risk of relapse (odds ratio 1.7; 95% CI, 1.2 to 3.4; p=0.05). Two-year cumulative risk of relapse (using the Kaplan-Meier) after auto-HSCT did not statistically significantly differ in MRD-negative patients receiving (n=15) and not receiving (n=10) maintenance therapy with bortezomib (p=0.58). After completion of maintenance treatment, 42% of the MRD-positive patients achieved a negative status. In the MRD-positive patients who had received maintenance therapy, the average time to recurrence was 5 months longer than that in the naïve patients: 17.3 versus 12.3 months.The MRD status determined in MM patients who have achieved CR after auto-HSCT is an important factor for deciding on the use of maintenance therapy.Цель исследования. Определение эффективности поддерживающей терапии бортезомибом у больных множественной миеломой (ММ), достигших полной ремиссии (ПР) после трансплантации аутологичных гемопоэтических стволовых клеток (ауто-ТГСК) в зависимости от наличия минимальной остаточной болезни (МОБ). Материалы и методы. С января 2014 г. по февраль 2016 г. 52 больных ММ (19 мужчин и 33 женщины) в возрасте от 24 до 66 лет (медиана 54 года), достигшие ПР после ауто-ТГСК, рандомизировали для проведения поддерживающей терапии бортезомибом в течение года. На 100-й день после ауто-ТГСК всем больным выполняли иммунофенотипирование плазматических клеток костного мозга методом 6-цветной проточной цитометрии с целью выявления МОБ. В качестве критерия оценки эффективности поддерживающей терапии выбрана безрецидивная выживаемость (БРВ). Результаты. Двухлетняя БРВ больных с МОБ-негативным статусом после ауто-ТГСК статистически значимо (р=0,05) превышала БРВ больных с позитивным по МОБ статусом: 52,9% (при 95% доверительном интервале - ДИ от 35,5 до 70,5%) против 37,2% (при 95% ДИ от 25,4 до 49,3%). Наличие МОБ статистически значимо увеличивало риск развития рецидива (отношения рисков 1,7 при 95% ДИ от 1,2 до 3,4; p=0,05). Двухлетняя кумулятивная вероятность (по Каплану-Мейеру) рецидива после ауто-ТГСК у больных с негативным по МОБ статусом, получавших (n=15) и не получавших (n=10) поддерживающую терапию бортезомибом, статистически значимо не различалась (р=0,58). После завершения поддерживающего лечения 42% позитивных по МОБ больных достигли негативного статуса. Среднее время до развития рецидива заболевания в группе позитивных по МОБ больных, получавших поддерживающую терапию, оказалось на 5 мес больше, чем у больных без поддерживающей терапии: 17,3 мес против 12,3 мес. Заключение. Статус по МОБ, определяемый у больных ММ, достигших ПР после ауто-ТГСК, является важным фактором для принятия решения о назначении поддерживающей терапии.