Background: Myelodysplastic syndromes (MDS) can present a challenge for clinicians. Multicolor flow cytometry (MFC) can aid in establishing a diagnosis. The aim of this study was to determine the optimal MFC approach for MDS. Methods:The study included 102 MDS (39 low-grade MDS), 83 cytopenic patients without myeloid neoplastic disorders (control group), and 35 healthy donors. Bone marrow was analyzed using a six-color MFC. Analysis was conducted according to the "Ogata score," "Wells score," and the integrated flow cytometry (iFC) score. Results:The respective sensitivity and specificity values were 77.5% and 90.4% for the Ogata score, 79.4% and 81.9% for the Wells score, and 87.3% and 87.6% for the iFC score. Specificity was not 100% due to deviations of MFC parameters in the control group. Patients with paroxysmal nocturnal hemoglobinuria (PNH) had higher levels of CD34 + CD7 + myeloid cells than donors. Aplastic anemia and PNH were characterized by a high proportion of CD56 + cells among CD34 + precursors and neutrophils. The proportion of MDS-related features increased with the progression of MDS. The highest number of CD34 + blasts was found in MDS with excess blasts.MDS with isolated del(5q) was characterized by a high proportion of CD34 + CD7 + cells and low granularity of neutrophils. In 39 low-grade MDS, the sensitivities were 53.8%, 61.5%, and 71.8% for Ogata score, Wells score, and iFC, respectively. Conclusion:The results support iFC as a useful diagnostic tool in MDS.

Objective. To analyze treatment results of 172 patients with acute myeloid leukemia (AML) aged 18-60 years in National Medical Research Center for Hematology of MHRF. Materials and methods. Inductive and consolidation program for 139 (80%) patients was based on a standardized protocol: 4 courses “7+3” with different anthracycline use (2 courses of daunorubicin, idarubicin, mitoxantrone) and continuous use of cytarabine on the second inductive course. In 20% of patients cytarabine courses at the dose of 1 g/m2 2 times a day for 1-3 days combined with idarubicin and mitoxantrone were used as two consolidation courses. Allogenic bone marrow transplantation was performed in the first complete remission (CR) period in 40% of patients. Results. The frequency of CR achievement in all patients was 78.6%, refractory forms were observed in 13.9% of patients, early mortality - in 7.5% of patients. Seven-year overall survival (OS) rate was 40.7%, relapse free survival (RFS) - 43.2%. When estimating effectiveness depending on cytogenetic risk group it was demonstrated that 5-year OS and RFS in patients with translocation (8; 21) cannot be considered as satisfying, it accounted for 50 and 34%, respectively. At the same time in patients with 16th chromosome inversion (inv16) these characteristics accounted for 68.6 and 63.5%. Acquired results forced reconsidering of the consolidation program in AML patients of this subgroup. The median time to allogenic blood stem cells transplantation (allo-BSCT) in patients with first CR was 6.5 months that was taken as a reference point in landmark analysis of patients in whom allo-BSCT was not performed. Landmark analysis showed that in AML patients of favorable prognosis group allo-BSCT does not significantly reduce the probability of relapse (0 and 36%) and does not influence RFS (33 and 64%). In patients of border-line and poor prognosis allo-BSCT significantly reduces relapse probability (26 and 66%; 20 and 100%) and significantly increases a 7-year RFS (68.7 and 30%; 45.6 and 0%). Allo-BSCT also results in significant RFS increase and reduces the probability of relapse (25 and 78%) in patients in whom CR was achieved only after the second induction course. At the same time allo-BSCT does not influence patients who achieved CR after the first treatment course: 55 and 50%. Conclusion. Multivariate analysis showed that cytogenetic risk group (HR=2.3), time of CR achievement (HR=2.9), and allo-BSCT transplantation (HR=0.16) are independent factors for disease relapse prognosis after achieving CR.

Introduction The presence of the CD157 GPI-protein on both monocytes and granulocytes only gives opportunity to use it as a target for paroxysmal nocturnal hemoglobinuria (PNH) phenotype cells detection instead of CD24 and CD14, thus improving the technique of PNH-cells evaluation. In present study we used standard technique (International Clinical Cytometry Society (ICCS) guideline proposal) together with 5 color combination of mAbs for detection of PNH-clone on the monocytes and granulocytes simultaneously in one test-tube. Objectives: improvement of PNH cells detection technique. Materials and methods: Blood samples were collected from 37 patients (pts) with bone marrow failure syndrome (aplastic anemia – 34 pts., PNH - 2 pts., myelodysplastic syndrome – 1 pt.; 23 female and 14 men; median age 24 (15 to 66). PNH clone was detected by flow cytometry in all 37 pts. Three healthy donors were in control group. The comparison of the standard 4-color technique of PNH clone size detection on monocytes (FLAER, CD14, CD64, CD45 reagents) and on granulocytes (FLAER, CD24, CD15, CD45 reagents) with the 5-color technique using CD157 GPI-protein antibodies for the both cells populations in one test-tube (FLAER, CD157, CD15, CD64, CD45) were performed. Results: Both methods showed the same high sensitivity for determining of PNH clone. The correlation coefficient was 0,9994 for granulocytes and 0,9924 for monocytes (Figure 1). Figure 1 Figure 1. In group of patients with minor PNH-clone (range from 0,01% to 0,99%) the clone size was twice times bigger on monocytes compared to granulocytes using the standard method, whereas with antibodies against CD157 this difference disappeared. In patients with PNH-clone between 1% and 10% the clone was nearly three times less on granulocytes than monocytes using both methods; in the group with clone more than 10% there was no differences between cells populations. Table 1. Average value of PNH clone on leukocytes in groups of patients both techniques PNH clone Gr, % (mean) Mon, % (mean) CD24-/FLAER- CD157-/FLAER- CD14-/FLAER- CD157-/FLAER- 0%-0,99% 0,178 0,349 0,323 0,378 1%-9,99% 3,98 3,76 9,54 9,98 >10% 71,52 71,52 71,85 71,34 Conclusion: The results of the PNH clone detection obtained with CD157 mAbs are comparable with the standard technique proposed by ISSC. However, the use of CD157 antibodies has important advantage: the PNH clone size detection in one test-tube with 5-color combination reduces time and expenses. Additionally, using of 5-color CD157 antibodies kit would be preferable for the monitoring and detection of minor PNH clone. Disclosures No relevant conflicts of interest to declare.

Introduction. At the initiative of the Russian Hematology Society, the research group for the study of idiopathic aplastic anemia has developed clinical recommendations for the diagnosis and treatment of idiopathic aplastic anemia.Aim: to standardize diagnostic and therapeutic approaches for the treatment of acquired aplastic anemia in Russia.Methods. The methodological approaches used are based on the principles of evidence-based medicine, based on the recommendations of the Russian council of experts on the diagnosis and treatment of patients with idiopathic aplastic anemia, Russian and international experience in managing patients, and the recommendations of the European group for the study of aplastic anemia.Results. A new revised and updated version of the national clinical guidelines is presented.Conclusion. These recommendations are intended for doctors of various specialties, health administrators, and medical school students.Conflict of interest: the authors declare no conflict of interest.Financial disclosure: this study did not have sponsorship.

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.