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 <0.05). The abnormal T cell subpopulation ratios that cause abnormal immune response are most pronounced in the very severe form of AA. When responding to treatment, no significant changes in T cells subpopulation were found either before the start of IST or 6 months after compared with donors. In the absence of treatment response, a higher proportion of effector CD4+ and CD8+ T cells, memory CD4+ T cells, and a lower proportion of naive CD4+ and CD8+ T cells were detected compared to donors already before the start of IST (p <0.05). Of all cytometric parameters, a significant relationship was obtained between effector CD8+ T cells dynamics and response to treatment (p = 0.040). The number of these cells at the onset and control points significantly correlated with the response to IST. In patients who have not responded to treatment by the 3rd month from IST initiated, there is a further increase in effector CD8+ T cells number, despite the IST continuation, which dictates the need to intensify IST in the shortest possible time (between the 3rd and 6th months) in these patients, namely, a 2nd course of equine antithymocyte globulin and continuation of cyclosporine therapy or individual consideration of alternative treatment (allogeneic hematopoietic stem cell transplantation).Conclusion. Studying the T cells subpopulation dynamics, in particular effector T cells, allows us to determine the tactics of further treatment in the early stages of IST in order to select the optimal treatment program for each AA patient.

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 <0.05). There was a tendency to increase the frequency of new chromosomal aberrations in patients with shorter telomere length.Conclusion. The results obtained do not contradict previous studies and show the association of a decrease in baseline telomere length with poor response to IST and a high risk of clonal complications. The determination of telomere length should be used both in differential diagnosis between the acquired disease and congenital bone marrow failure syndromes, and for timely choice of patient management tactics (IST or allogeneic hematopoietic stem cell transplantation).

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.

The differentiation potential of individual clones of fibroblast CFU (CFU-F) was studied and the relative expression level of genes was analyzed in the culture of CFU-F from the bone marrow in patients with non-severe and severe forms of aplastic anemia at the onset of the disease. The differentiation potential of CFU-F clones was determined by the relative expression of marker genes using quantitative PCR. In aplastic anemia, the ratio of CFU-F clones with different differentiation potential changes, but the molecular mechanisms of this phenomenon are different in non-severe and severe aplastic anemia. In the culture of CFU-F in non-severe and severe aplastic anemia, the relative expression level of genes associated with the maintenance of the hematopoietic stem cell in the bone marrow niche changes, but the decrease in the expression of immunoregulatory genes occurs in severe form only, which may reflect differences in the pathogenesis of non-severe and severe aplastic anemia.

The properties of bone marrow-derived multipotent mesenchymal stromal cells (MSC) of patients with aplastic anemia at the onset of the disease are studied insufficiently. The aim of this work was to test the ability of MSC from patients with aplastic anemia to maintain hematopoietic precursors and to analyze the expression of genes associated with hematopoiesis and immune response. The ability of MSC to maintain hematopoietic precursors was determined by counting cobblestone area-forming cells; gene expression was analyzed by quantitative PCR. It was shown that MSC of patients with aplastic anemia preserve their ability to maintain hematopoietic precursors. Pronounced changes in the expression of the VEGFA and ANGPT1 genes were found. MSC from aplastic anemia patients with PNH clone significantly differ from those from aplastic anemia patients without PNH clone in terms of the expression of the SDF1, IL1R, and VEGFA genes. Changes in gene expression can be associated with the pathogenesis of the disease.

The article explores modeling the development of ovarian cancer, the treatment of this oncologicaldisease in women, the assessment of the time to achieve remission, and the assessment of the time of the onset of relapse. The relevance of the study is that ovarian cancer is one of the most common cancers in women and has the highest mortality rate among all gynecological diseases. Modeling the process of the development of the disease makes it possible to better understand the mechanism of the development of the disease, as well as the time frame of the onset of each stage, as well as the assessment of the survival time. The aim of the work is to develop a model of an ovarian tumor. It is based on a model of competition between two types of cells: epithelial cells (normal cells) and tumor cells (dividing cells). The mathematical interpretation of the competition model is the Cauchy problem for a system of ordinary differential equations. Treatment is seen as the direct destruction of tumor cells by drugs. The behavior of solutions in the vicinity of stationary points is investigated by the eigenvalues of the Jacobi matrix of the right side of the equations. On the basis of this model, the distribution of conditional patients by four stages of the disease is proposed. Biochemical processes that stimulate the accelerated growth of the tumor cell population are modeled by a factor that allows tumor cells to gain an advantage in a competitive relationship with epithelial cells. The spatio-temporal dynamics of an ovarian tumor leads to a modification of the competition model due to the introduction of additional factors into it, taking into account the presence of increased nutrition of ovarian tumors, the exit of the tumor from the plane of the ovary, as well as the effect of treatment on tumor cells. The new model describes the interaction conditions with a system of second-order partial differential equations. The results of computer modeling demonstrate an assessment of the distribution of conditional patients by stages of the disease, the time of onset of relapse, the duration of remission, the obtained theoretical results of modeling are compared with the real data.

Background. 6-mercaptopurine (6-MP) is a drug that is included in the treatment protocols for children and adults with acute lymphoblastic leukemias/lymphomas (ALL/LBL). It is known that individual differences in 6-MP tolerance can be explained by the TPMT and NUDT15 polymorphisms.Aim. To determine 6-MP toxicity profile in adult patients with Ph-negative ALL/LBL treated by ALL-2016 protocol, depending on the TPMT and NUDT15 polymorphisms.Materials and methods. The study included 54 adult patients with Ph-negative ALL/LBL (40 male and 14 female). The median age was 31 (18-51) years. T-ALL/LBL was diagnosed in 29 patients, B-ALL/LBL - in 22, acute leukemia with a mixed immunophenotype - in 3. All patients received treatment according to the multicenter study ALL-2016 (ClinicalTrials.gov, NCT03462095). polymorphisms in NUDT15 (*2, *3) and TPMT (*2, *3A, *3B, *3C) genes were detected using the allele-specific real-time polymerase chain reaction. Genomic DNA was extracted from patients peripheral blood samples. On the induction and consolidation therapy by the protocol, the received and proper 6-MP doses were calculated for all the patients. Drug toxicity was evaluated based on clinical and laboratory data.Results. TPMT and NUDT15 polymorphisms were detected in 11 (20 %) patients, more often in B-ALL - 7 (32 %) of 22 (p <0.05). A lower dose of 6-MP was received by patients with TPMT, NUDT15 polymorphisms only at consolidation IV (p = 0.01). we didn't find a correlation between the 6-MP toxicity and the polymorphisms in our patients (p >0.05).Conclusion. There were no differences in the received dose of 6-MP and the incidence of toxicity in adult patients between Ph-negative ALL/LBL with or without TPMT and NUDT15 polymorphisms treated according to ALL-2016 protocol (p >0.05). further studies including evaluation of 6-MP metabolites concentrations are required for a more complete understanding of the metabolism of this drug.

Introduction. The use of thrombopoietin receptor agonists, especially eltrombopag, in the treatment of aplastic anemia (AA) patients who did not respond to the previous immunosuppressive therapy (IST), is accompanied by the development of a hematological response in 40–60 % of patients.Aim — to study the effi cacy of using eltrombopag in treatment programs for AA patients refractory to previous IST.Methods. The study included 20 AA patients who were treated at the National Research Center for Hematology from 2015 to 2020. These patients did not respond to the conducted IST (ATG + CsA). Eltrombopag was administered at a dose of 150 mg/day. The results of treatment were assessed at 3 and 6 months: the achievement of hematological improvement, partial and complete remission, as well as the identifi cation of possible clonal evolution were determined.Results. Eleven out of 20 (55 %) patients responded to treatment: 2 patients developed hematological improvement, 6 patients — partial remission, 3 patients — complete remission. All 11 patients responded to treatment within 12 months from the start of eltrombopag, but further positive dynamics of hematological parameters are possible. The median duration of treatment with eltrombopag was 11 (1–48) months. Most of the patients were treated with eltrombopag in combination with CsA. The duration of the course of treatment with eltrombopag depended on the response received (stable hematological improvement, remission, as well as the detection of clonal evolution) or its absence and the need for ATG or BMT. An aberrant karyotype was found in 2 AA patients who received eltrombopag: in one patient monosomy of chromosome 7 was detected 1 month after the start of treatment, in another patient, 37 months later, a clone with a derivative of chromosome 16 from t(1;16) and subclone with complex disorders of the karyotype without signs of myelodysplasia in the bone marrow.Conclusion. The inclusion of the TPO receptor agonist eltrombopag in the treatment program for AA patients allows for a stable hematological response and remission of AA for patients who have not responded to IST. The effectiveness of eltrombopag is determined by adherence to the treatment algorithm, the optimal duration of the course, and the dose of the drug used. There is still a need for long-term observation of the patient and control morphological and cytogenetic studies.

Treatment programs for patients with acquired aplastic anemia include two main therapeutic options: allogeneic bone marrow transplantation and combined immunosuppressive therapy (IST). However, combined IST remains the method of choice for most adult AA patients. This study included 120 AA patients who received IST at the National Research Center for Hematology in 20072016. The analysis was applied to 120 patients. Median age was 25 (1765) years, M/F: 66/54, SAA/NSAA: 66%/34%. Effectiveness of IST was carried out in 120 patients with AA. This group did not include 8 SAA patients who died during the first 3 months from the start of treatment from severe infectious complications (early deaths 6.2%) and 2 AA patients who dropped out of surveillance. The observation time was 55 (6120) months. Paroxysmal nocturnal hemoglobinuria (PNH clone) was detected in 67% of AA patients. The median PNH clone size (granulocytes) was 2.5 (0.0199.5)%. The treatment was according to the classical protocol of combined IST: horse antithymocytic globulin and cyclosporin A. Most of patients (87%) responded to combined immunosuppressive therapy. To achieve a positive response, it was sufficient to conduct one course of ATG to 64% of patients, two courses of ATG 24% of patients and 2% of patients responded only after the third course of ATG. A positive response after the first course was obtained in 64% of patients included in the analysis. Most of the responding patients (93%) achieve a positive response after 36 months from the start of treatment. Therefore, the 3rd6th months after the first course of ATG in the absence of an answer to the first line of therapy can be considered the optimal time for the second course of ATG. This tactic allows to get an answer in another 58% of patients who did not respond to the first course of ATG. The probability of an overall 10-year survival rate was 90% (95% confidence interval 83.696.2).

Introduction. The main pathogenetic mechanism of the development of aplastic anemia (AA) is a violation of the immune regulation of hematopoiesis.Aim: to study of the subpopulation composition of T-cells and the repertoire of the T-cell receptor in AA patients.Patients and Methods. The study included AA patients (n = 40) without prior immunosuppressive therapy in 2018–2020. The T-cell subpopulation structure and T-cell receptor Vβ-family (TCR-Vβ) oligoclonality were studied in samples of bone marrow using flow cytometry.Results. We report characteristic properties of T-cell subpopulations of bone marrow in all AA patients: elevated counts of cytotoxic T-cells, effector CD4+ and CD8+ cells, CD4+ memory cells, which may suggest a long-term antigenic stimulation with subsequent activation of these cell subpopulations resulting in hyperexpression of pro-inflammatory cytokines. Diminishing of naive CD4+ and CD8+ cells, regulatory and double negative T-cells may indicate a relaxing control of cytokine-producing T-cells. A relationship has been established between the AA severity and counts of effector, regulatory, double negative and PD-1 positive T-cells. A highest count of potentially cytokine-producing T-cells and lowest count of cells involved in T-cell activity regulation were observed in very severe AA patients. Studies of the TCR-Vβ repertoire revealed oligoclonal expansion in the cytotoxic T-cell subpopulation.Conclusion. Enrichment in selected Vβ families suggests autoreactive T-cell clonality and attests to the immune nature of AA. A dynamic TCR-Vβ repertoire assay may be recommended in the disease monitoring. Flow cytometry helps identify valuable biomarkers for T-cell clone monitoring in AA and a better assessment of the disease progression.

The paper proposes mathematical models of ovarian neoplasms. The models are based on a mathematical model of interference competition. Two types of cells are involved in the competition for functional space: normal and tumor cells. The mathematical interpretation of the models is the Cauchy problem for a system of ordinary differential equations. The dynamics of tumor growth is determined on the basis of the model. A model for the distribution of conditional patients according to four stages of the disease, a model for assessing survival times for groups of conditional patients, and a chemotherapy model are also proposed.

Background: Diamond Blackfan anemia (DBA) is a rare congenital bone marrow failure disorder, characterized by severe hypoplastic anemia, associated congenital anomalies, and an increased risk of developing cancer. Based on the underlying mutations in ribosomal protein (RP) genes, DBA is classified as a ribosomopathy. While disruptions in ribosomal biogenesis would be expected to have global effects, hematological in DBA are primarely of the erythroid lineage. Moreover, since cellular determinants following ribosomal stress are still not well understood, and most functional studies are performed in models representing only the most frequently affected RP-genes, the development of novel therapeutic strategies for all DBA patients has been been hampered. Here we propose, for the first time, a novel untargeted metabolomics approach to study anemia in DBA patient cells. Metabolomics is the large-scale, unbiased study of metabolites and their interactions within a biological system, and a powerful functional tool, directly reflecting the underlying biochemical activity and the state of cells. The DBA-metabolome can be used to study commonly deregulated cellular pathways during erythroid development, irrespective of the underlying molecular defect. Aims: Defining a metabolic signature of RP-deficiency in DBA, will 1. Increase our understanding of erythroid-specific defects in DBA, and 2. Contribute to the identification of potential novel therapeutic targets. Methods: Quantification of metabolites was performed on dried blood spots from 6 DBA patients (RPS26, RPL5, RPL9, unknown) by direct infusion high resolution mass spectrometry (DI-HRMS) followed by an untargeted metabolomics pipeline. For annotation, the Human Metabolome Database (HMDB) was used. Results were compared with dried blood spots samples of 10 healthy controls. Results: Preliminary data from 6 DBA patients with different genotypes demonstrate a significant increase in intermediates of the pentose phosphate pathway (PPP) (Figure 1A). This indicates that the PPP is upregulated in red blood cells from DBA patients, regardless of the underlying molecular defect. In line with this we observed a significant increase in erythrocyte reduced glutathione (GSH) content in 9 DBA patients (RPS26, RPL5, RPL11, unknown), compared to 12 controls (Figure 1B). In red blood cells the PPP mainly serves to provide the cell with sufficient amounts of NADPH to maintain high intracellular levels of GSH, which is needed to protect the cell against oxidative damage. Our results therefore support a role for oxidative stress response in DBA pathophysiology irrespective of the underlying genotype. Figure 1. (A) Increase in metabolites involved in PPP in DBA patient cells. (B) Increased GSH concentration in DBA patient erythrocytes.Summary/Conclusion: DBS metabolomics can be used as a novel functional tool to investigate deregulated cellular pathways in DBA irrespective of the underlying molecular defect. This will contribute to increased insights in cell type specific phenomena and DBA pathophysiology in general.

Introduction. The pathogenesis of acquired aplastic anaemia (AA) is based on immune-mediated development of bone marrow failure. The absence of clear reasons for the development of immune aggression determines the relevance of investigations aimed at studying genetic disorders in the remaining pool of hematopoietic stem cells, in the hematopoietic niche, as well as mechanisms underlying the failure of immunological tolerance. Aim. The present literature review describes the most relevant markers used for characterising AA patients on the basis of their possible response to immunosuppressive therapy (IT) and for forming groups being at risk of developing refractoriness and clonal evolution. General findings. The overall survival probability in patients with AA following program IT is comparable to the results of transplanting allogeneic hematopoietic blood stem cells (allo-HSCT) from a related donor in the first line of therapy. According to current Russian and international recommendations, the tactics for treating AA patients is determined by the patient's age and the presence of an HLA-identical sibling. Allo-HSCT from a related HLA-identical donor is a method used for treating patients younger than 40 years; however, the possibility of performing allo-HSCT is limited by donor availability. Although the event-free survival probability during IT is inferior to the results of allo-HSCT, IT remains the main treatment method for most patients with AA. In order to minimise adverse outcomes, it is necessary to consider predictors of treatment efficacy along with the likelihood of developing late clonal evolution as early as at the AA diagnosis stage. Patient evaluation and formation of risk groups will facilitate selection of the most optimal treatment approach at the therapy planning stage, which includes either IT combination with thrombopoietin receptor agonists, or a search for an unrelated HLA-compatible donor and timely allo-HSCT.

The implementation of principles of highly sensitive flow cytometry into diagnostic of paroxysmal nocturnal hemoglobinuria increased rate of detection of paroxysmal nocturnal hemoglobinuria clone in patients with aplastic anemia already at early stages of diagnosis establishment (up to 79%). However, detection of paroxysmal nocturnal hemoglobinuria clone attracts interest not only from point of view of progression in % of patients with aplastic anemia). The occurrence of paroxysmal nocturnal hemoglobinuria clone in patients with aplastic anemia can be accompanied by hidden disorders of haemopoesis with increasing risk in conditions of proliferative stress. Hence, it is necessary to monitor the given clone during all period of observation. The study is a prospective investigation analyzing dynamics of paroxysmal nocturnal hemoglobinuria clone in process of immune suppressive therapy applied to 44 patients with aplastic anemia. The mentioned clone was initially detected in 59.6% of patients. The median of observation amounted to 27 (9-48) months. Depending on size of granulocytic paroxysmal nocturnal hemoglobinuria clone patients were allocated in four conditional groups: group I - from 0.01% to 0.99% (n=11); group II - from 1% to 9.99% (n=8); group III - from10% to 49.9% (n=4); group IV - from 50% and more (n=5). In the course of study the differently directed dynamics of paroxysmal nocturnal hemoglobinuria clone was revealed. In 3 out of 11 patients from group I median of paroxysmal nocturnal hemoglobinuria clone increased from minor values (less than 1%) to 3.55%; at that in one patient occurred total elimination of paroxysmal nocturnal hemoglobinuria clone to 12th month of observation. The noticeable unidirectional dynamics was established in patients of group III: already to 3d month of observation, simultaneously with becoming of remission, median of size of paroxysmal nocturnal hemoglobinuria clone in group diminished from 22.9% (18.39%-24.77%) to 5.6% (1.5%-6.7%). Among patients of groups II and IV paroxysmal nocturnal hemoglobinuria clone remained stable. The development of hemolytic form of paroxysmal nocturnal hemoglobinuria was observed in all patients of group IV i.e. in 18% of patients with aplastic anemia with primarily detected paroxysmal nocturnal hemoglobinuria clone. In the process of observation, in 37% of patients with aplastic anemia without primarily detected paroxysmal nocturnal hemoglobinuria clone its occurrence and persistence (median - 0.34% (0.1%-6.2%)) was noticed. According to the results of study, alteration of sizes of paroxysmal nocturnal hemoglobinuria clone or its occurrence develop in case of response to ISP and, most probably, depend on advantage of growth in the process of repair of normal (GPI positive) or clonal (GPI negative) hemopoiesis. To acquire more reliable conclusions will be possible through development of techniques of molecular diagnostic simultaneously with dynamic observation of course of disease in the given patients.