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Telomere length can be measured by polymerase chain reaction (PCR), allowing to obtain the absolute length of telomeres (ALT) in base pair, and by flow cytometry, which can only estimate the relative telomere length. The aim of the study was to compare the results of the two methods and to develop an accurate and reliable way of converting the relative telomere length to absolute. The peripheral blood from 21 donors was analyzed. Measurement of leukocyte telomere length by flow cytometry was carried out using a commercial Telomere PNA Kit / FITC (Dako, Denmark) with two CytoFLEX flow cytometers (Beckman Coulter, China) and BD FACSCanto II (Becton Dickinson, USA), obtaining the molecular equivalent of fluorescence (MEF). To measure telomere length by real-time PCR, calibrators with a known number of telomeric repeats were prepared. Two quantitative PCRs were carried out: one for telomeric repeats, the other for determining the number of genome-equivalents of DNA, three times for each sample, which made it possible to calculate ALT. A strong direct relationship was found between the MEF obtained with BD FACSCanto II and CytoFLEX (r = 0.97). Analysis of PCR and flow cytometry results showed a significant correlation between ALT and MEF. We calculated the regression equations of ALT and MEF for CytoFLEX - y = 0.0043x (r = 0.84) and for BD FACSCanto II - y = 0.0051x (r = 0.82). Correlation analysis showed a high comparability of telomere lengths measured by two methods. The obtained regression equations allow converting the results of flow cytometry into absolute values, allowing the comparison of the results of different research groups and the use of this method in clinical trials.

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.

We studied the effect of autologous and allogeneic lymphocytes on multipotent mesenchymal stromal cells in co-culture. It is shown that changes in multipotent mesenchymal stromal cells and in lymphocytes did not depend on the source of lymphocytes. Contact with lymphocytes triggers expression of HLA-DR molecules on multipotent mesenchymal stromal cells and these cells lose their immune privilege. In multipotent mesenchymal stromal cells, the relative level of expression of factors involved in immunomodulation (IDO1, PTGES, and IL-6) and expression of adhesion molecule ICAM1 increased, while expression of genes involved in the differentiation of multipotent mesenchymal stromal cells remained unchanged. Priming of multipotent mesenchymal stromal cells with IFN did not affect these changes. In turn, lymphocytes underwent activation, expression of HLA-DR increased, subpopulation composition of lymphocytes changed towards the increase in the content of naïve T cells. These findings are important for cell therapy.

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.

Analysis of changes in lymphocyte subpopulations during co-culturing with multipotent mesenchymal stromal cells (MSC) revealed two distinct MSC groups: one group (A) increased HLA-DR expression on lymphocytes during co-culturing and the other (B) did not change it in comparison with lymphocyte monoculture. In stromal cells interacting with lymphocytes, expression of HLA-DR molecules was initiated, but only in samples that induced enhanced expression on lymphocytes and irrespectively of whether allogeneic or autologous lymphocytes were used for co-culturing with MSC. In group A, the relative expression of IDO1 significantly increased in comparison with group B. The revealed individual differences in MSC can explain why not all MSC samples are effective in the treatment of autoimmune diseases, acute "graft-versus-host" disease, and other pathologies.

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.

We studied changes in the population of human multipotent mesenchymal stromal cells activated by IFNγ. The cells were cultured under standard conditions; IFNγ was added in various concentrations for 4 h or over 2 passages. It was shown that the total cell production significantly decreased after long-term culturing with IFNγ, but 4-h exposure did not affect this parameter. After 4-h culturing, the expression levels of IDO1, CSF1, and IL-6 increased by 300, 7, and 2.4 times, respectively, and this increase persisted 1 and 2 days after removal of IFNγ from the culture medium. The expression of class I and II MHC (HLA) on cell surface practically did not change immediately after exposure to IFNγ, but during further culturing, HLA-ABC (MHC I) and HLA-DR (MHC II) expression significantly increased, which abolished the immune privilege in these cells, the property allowing clinical use of allogenic multipotent mesenchymal stromal cells. Multipotent mesenchymal stromal cells can suppress proliferation of lymphocytes. The degree of this suppression depends on individual properties of multipotent mesenchymal stromal cell donor. Treatment with IFNγ did not significantly affect the intensity of inhibition of lymphocyte proliferation by these cells.