Introduction. The COVID-19 pandemic has changed the conditions for providing medical care to hematological patients, including those who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Objective: to analyze the course of the new coronavirus infection COVID-19 in patients who have undergone allo-HSCT. Materials and methods. The retrospective study included 87 patients who developed COVID-19 after allo-HSCT in the period from March 2020 to January 2022. In most cases, transplants were performed in patients with acute leukemia (77 %) using peripheral hematopoietic stem cells (52 %) or bone marrow (48 %) after conditioning in a reduced intensity mode (75 %). COVID-19 infection was considered confi rmed when SARS-CoV-2 RNA was detected by PCR in a smear from the oropharyngeal/nasopharyngeal mucosa.

Results. In 71 (81.6 %) patients, COVID-19 was established a year after performing allo-HSCT, in 16 (18.4 %) patients — during the fi rst year after allo-HSCT. The median age at the time of the development of a new coronavirus infection was 42 years. At the time of the COVID-19 debut, 39 (45 %) patients received immunosuppressive therapy (IST). Performing IST at the time of diagnosis of COVID-19 had a negative effect on overall survival (p = 0.0001). A total of 7 (9 %) patients suffered from the disease asymptomatically, 39 (45 %) — in mild form, 23 (26 %) — in moderate, 10 (11 %) — in severe and 8 (9 %) — in critical form. TCR-αβ/CD19⁺ graft depletion was associated with a milder course of COVID-19 infection in patients after allo-HSCT (p = 0.06). Hospitalization in a 24-hour hospital was required in 24 (27 %) cases.

Conclusion. Overall survival was comparable in the general group of patients with allo-HSCT compared with healthy individuals with COVID-19, due to a suffi cient degree of immune system reconstruction, as well as a small volume of the study group. The factors that increased the risk of an adverse outcome were age and male gender.

Introduction. Venous thromboembolism complications (VTE) are prevalent severe complications observed in patients with malignant tumors. The low sensitivity and specifi city of modern scores in diagnosing VTE in these patients underscores the need to search for more effective methods of VTE diagnosis and prediction.

Aim: to assess the effi ciency of the thrombodynamics test in diagnosing hypercoagulation and prevention of VTE in patients with malignant tumors.

Materials and methods. The interim analysis included 269 patients with solid malignant tumors. The observation median value was 4.3 months. Blood tests for thrombodynamics were conducted using a thrombodynamics analyzer (HemaCore, Russia).

Results. The state of hemostatic system of this group of patients was characterized by the presence of pronounced hypercoagulation in 90 % of patients: parameter V (blood clot growth rate) > 29 μm/min in 90 % of patients. Once the antineoplastic therapy was initiated, hypercoagulation tended to decrease: median value V at the fi rst chemotherapy course was 59.9 μm/min, while median value V 3 months into chemotherapy was 56.2 μm/min (p < 0.05). With an observation median value of 4.3 months, hypercoagulation resulted in VTE complications in 14 % of patients. The Khorana score points were not reliable VTE predictors. ROC analysis of the thrombodynamics data showed that the parameter value of V higher than 40.7 μm/min was an accurate predictor of a thromboembolic event with sensitivity of 60 % and specifi city of 78 %. A relative risk of thrombosis calculated using this cut-off value was 2.7 (95 % confi dence interval 1.6–4.7; p < 0.001).

Conclusion. Thrombodynamics is a promising method for predicting VTE complications in patients with malignant tumors. This method has exhibited higher sensitivity and nearly comparable specifi city when contrasted with the Khorana score. Using this test in clinical practice facilitates the identifi cation of a group of patients who have a high risk of VTE complications and are in need of a preventive anticoagulant therapy while their Khorana score points are not elevated.

Introduction. Highly accurate determination of hemostatic indices of plasma and blood plasma products is important for industrial transfusiology and monitoring the effi cacy of their clinical application. Repeated measurements increase statistical power, thereby reducing the likelihood of committing a second-order error, which is described as a false negative result and occurs when a test fails to detect a truly existing effect.

Aim: to evaluate the effect of increasing the number of repeated measurements on the accuracy of factor VIII activity and fi brinogen concentrations in donor plasma.

Materials and methods. Human donor plasma used in the study was obtained by centrifugation of whole blood. The criterion for inclusion of biomaterial in the study was the presence of a non-repeatable combination of donor characteristics: sex, age, blood group and Rhesus affi liation by the presence of D antigen. Whole blood donors for this work were male and female aged between 38 and 53 years with groups: O(I), A(II) and B(III). 27 repeated measurements of factor VIII activity by the one-stage clotting method and fi brinogen concentrations by the Clauss clotting method were performed on automatic coagulometer ACL TOP 300 with HemosIL reagents.

Results. For factor VIII activity, the difference in values recorded in repeated measurements reached 20 IU/100 ml, and for fi brinogen concentrations the maximum difference was 0.29 g/L. The calculation of the change in the size of the confi dence interval with increasing number of repeated measurements is presented. While the decrease in size from the second to the fourth repeated measurement averaged 83.5 % for the measurement of factor VIII activity and 61.7 % for fi brinogen concentrations, from the fi fth to the seventh it was 16.9 % and 21.5 %, respectively.

Conclusions. Despite the pre-analytical measures taken to reduce random error, blood plasma parameters of the same donation can take values in a wide range. Increasing the number of repeat measurements from one to three in the case of measuring factor VIII activity and fi brinogen concentrations is an effective means of improving the accuracy of these indices. However, with subsequent repeated measurements there will be a decrease in statistical power growth.

Introduction. Hemoglobinopathies are a group of diseases caused by aberrations in the HBB gene encoding the beta chain of globin. The range of possible aberrations is diverse and has regional specifi city.

Aim: to determine the laboratory and molecular genetic characteristics of beta-thalassemia and qualitative hemoglobinopathies.

Methods. In total, 268 patients suspected for having some types of the hereditary anemia were included in the study. All patients underwent capillary electrophoresis of hemoglobin using the Minicap Sebia device and the group either with elevated HbA2/HbF fractions or with the presence of pathological Hb variants was selected. The direct automatic Sanger sequencing of the HBB gene was performed in the selected group.

Results. The analyzed group had 33 electrophoresis positive patients out of 268. Some pathological variants of hemoglobin including HbS, Hb Shepherds Bush and an unknown pathological Hb variant were detected. According to the results of genotyping, aberrations in the HBB gene were detected in 24 of 33 patients, of which 21 patients confi rmed the presence of beta-thalassemia, the rest of the detected aberrations were characteristic of various hemoglobinopathies. The most common mutation characteristic of beta-thalassemia was HB:c.25_26delAA, which was detected in 33.3% of cases. The pathogenic effect of an aberration with previously unknown clinical signifi cance has been determined — HBB:c.93-36CT.

Conclusion. Capillary electrophoresis of hemoglobin can be used for beta-thalassemia screening. However, the diagnosis confi rmation is carried out by molecular genetic studies. The detected aberrations spectrum for beta-thalassemia and hemoglobinopathies is extremely diverse and it includes some extremely rare hemoglobinopathy types requiring further investigations.

Introduction. The clinical manifestations and approaches to the treatment of infections of the soft tissues of the perianal region developing in oncohematological patients differ signifi cantly from classical cryptogenic anorectal abscesses in immunocompetent patients.

Aim. To study the clinical characteristics and results of treatment of various forms of perinatal infections (PI) in patients with tumor diseases of the blood system

Main findings. This review presents variants of clinical forms of the infectious processes in the perianal region in patients with hematological malignancies, treatment methods corresponding to a certain clinical form of infection, and factors affecting prognosis.

Introduction. Acute tumor lysis syndrome (ATLS) is a life-threatening complication of treatment in children with highly aggressive lymphomas (III–IV stages) and acute leukemias accompanied by hyperleukocytosis (above 100×10⁹/L).

Aim. To conduct a literature review on the diagnosis, prevention and treatment of acute tumor lysis syndrome in pediatric diseases of the blood system.

Main findings. Data was searched in PubMed, ResearchGate and Elibrary using the keywords tumor lysis syndrome, acute tumor lysis syndrome, malignant lymphoproliferative diseases in children and malignant neoplasms in children, limited to clinical trials, original articles and reviews on individuals from birth to 18 years of age. The search criteria were met by 24 clinical trials and 38 literature reviews. ATLS was characterized by acute electrolyte and metabolic disorders, and in the absence of therapy led to multiple organ failure and death. The prevention and treatment of ALTS includes cytoreductive prephase, infusion therapy, and/or allopurinol or rasburicase. If conservative therapy proves ineffective, hemodiafi ltration is performed.

Introduction. Disruption of iron utilization by erythrocaryocytes with deposition of hemosiderin granules in the form of a ring is a pathognomonic sign of sideroblastic anemia. An integral part of the diagnosis of this type of anemia is the cytomorphological analysis of bone marrow aspirate with a cytochemical reaction to ring sideroblasts.

Aim — to present current methods of cytological and cytochemical diagnosis of sideroblastic anemia.

Main findings. A pathognomonic sign of sideroblastic anemia is the presence of ring sideroblasts in the bone marrow. Ring sideroblasts are considered to be erythrocaryocytes with granules of intramitochondrial iron located around the nucleus. It is only possible to diagnose ring sideroblasts using special cytochemical diagnostics, but this is carried out only in half of the laboratories that diagnose hematological diseases in the Russian Federation. The algorithm of laboratory diagnostics of sideroblastic anemia in the National Medical Research Center for Hematology is presented.

Introduction. Peripheral T-cell lymphomas (PTCL) — a rare group of lymphoproliferative diseases characterized by an aggressive course and an unfavorable prognosis. The group is represented by heterogeneous nosological forms, in which standard treatment options lead to unsatisfactory results. Aim: to present the protocols for the treatment of PTCL

Main findings. In total, 12 years of experience in the treatment of 724 patients with T-cell lymphomas (430 patients with primary cutaneous forms, 110 patients with leukemic variants and 184 with peripheral T-cell lymphomas) has been accumulated. The treatment results and therapeutic algorithms were analyzed. In the general group of patients, the 3-year overall survival (OS) and relapse-free survival (EFS) were 76 % and 70 %, respectively. The best treatment results were achieved in the groups of intestinal T-cell lymphoma, specifically (EATL), and angioimmunoblastic T-cell lymphoma (AITL), anaplastic large cell ALK-positive lymphoma (ALCL ALK+), and the worst — in the group of ALCL ALK- (5-year EFS 31 %). High-dose chemotherapy under the NHL BFM-90 program in the treatment of ALK+ ALCL allows achieving 10-year OS and EFS 87 % and 84 %, respectively, but the less toxic CHOEP program was not inferior in effectiveness: 5-year OS and EFS amounted to 93 % and 88 %, respectively. High survival rates of patients with EATL were achieved with the use of high-dose chemotherapy according to the LB-M-04 program followed by auto-HSCT in the first line of therapy: 5-year OS and EFS amounted to 79 % and 74 %, respectively. The positive role of AITL maintenance therapy has been shown: 5-year OS and EFS during its implementation amounted to 75 % and 49 % versus 41 % and 20 % in the absence of it. In the protocols for the treatment of extranodal NK/T cell lymphoma, radiation therapy was used in the first line of therapy, 5-year OS and EFS were 60 % and 42 %, respectively. The role of autologous hematopoietic stem cell transplantation (auto-HSCT) in all PTCL was evaluated: 5-year OS and EFS were 82 % and 58 % compared with 67 % and 49 % without auto-HSCT. The transplantation of allogeneic hematopoietic stem cells (allo-HSCT), even in the treatment of relapses of the disease, has shown its effectiveness: 9 out of 11 patients are alive and remain in remission of the disease.

Introduction. There are two main subgroups of acute megakaryocytic leukemia (AMKL): with and without Down syndrome (DS). In children, AMKL without DS is a rare disease that is often associated with a rearrangement of the NUP98, KMT2A (MLL) genes, sporadic translocations identified both as the only abnormalities and as part of a complex karyotype, early onset of the disease and extremely unfavorable clinical outcome.

Aim: to present a clinical case of AMKL in a girl without DS with acquired trisomy 21, der(5)t(1;5)(q23-25;q35) and t(3;8) (q21;q24).

Main findings. A clinical case of a patient who was diagnosed with AMKL without DS at the age of 1 year and 5 months, accompanied by hepatosplenomegaly, lymphadenopathy, with a rapidly progressive course and lack of response to chemotherapy is described. A standard cytogenetic study revealed acquired trisomy 21, as well as clonal secondary chromosomal rearrangements — der(5)t(1;5)(q23-25;q35) and t(3;8)(q21;q24). The revealed structural aberrations have not yet been described in children with AMKL. The presented observation shows that der(5)t(1;5)(q23-25;q35) and t(3;8)(q21;q24) in combination with acquired trisomy 21 in young children with AMKL may be factors of poor prognosis.

Introduction. Lymphoma from cells of the marginal zone in some cases can manifest itself only at the stage of histological transformation into aggressive lymphomas, including diffuse large B-cell lymphoma (DLBCL).

Aim: to present a clinical observation of lymphoma transformed at the time of diagnosis from marginal zone cells to DLBCL.

Main findings. A case report of relapsed DLBCL in the submandibular area is presented, which was observed for 11 years without treatment. At the time of relapse, a 81×43×88 mm mass in the lower lobe of the right lung with SUV max up to 19.27 was identified. Atypical resection of the lower lobe of the right lung was performed. Based on histology and immunohistochemistry, a diagnosis of DLBCL transformed from marginal zone B-cell lymphoma was established, with PCR confirming the identity of the clone of indolent and aggressive B-cell lymphoma. The patient received R-CHOP plus lenalidomide therapy and achieved complete remission.

Introduction. Lymphomatoid papulosis is a CD30-positive lymphoproliferative disease with primary skin lesions. One of the therapeutic options is the use of anti-CD30 monoclonal antibody brentuximab vedotin.

Aim — to present the clinical observation of the effective treatment of lymphomatoid papulosis in a 6–year-old patient using brentuximab vedotin.

Main findings. In patient K., 6 years old, after suffering from acute respiratory viral infection, the appearance of rashes was noted, located mainly on the skin of the extremities, represented by single infl ammatory papules of round shape, up to 6–8 mm in diameter, dense consistency upon palpation, with a smooth surface and a pinpoint area of white necrosis in the center of individual elements. A biopsy of one of the elements was performed. According to histological examination, a diagnosis was established: lymphomatoid papulosis, type A. Due to the ineffectiveness of therapy using topical glucocorticosteroids, oral administration of prednisolone, the patient was treated with brentuximab vedotin. A partial complete response was achieved.