Vol 24, No 4 (2025)

Introduction. Hematopoietic stem cell transplantation (HSCT) from an alternative donor is the main treatment option for patients with severe acquired aplastic anemia (AAA) refractory to combined immunosuppressive therapy with anti-thymocyte globulin and cyclosporine A. Although the outcomes of unrelated and haploidentical HSCTs have improved over the years, graft-versus-host disease (GVHD) continues to pose a major clinical challenge associated with significant morbidity and mortality.

Aim: to present the outcomes of unrelated and haploidentical HSCTs with TCRαβ-depleted grafts in patients with AAA.

Materials and methods. Eighty patients (42 males and 38 females) with AAA underwent HSCT between September 2012 and February 2022. The median age at transplantation was 10 (2.3–22.7) years. Seventy-eight patients received HSCT after relapse or refractory disease after one (n = 14) or two (n = 18) courses of immunosuppressive therapy. Two patients underwent HSCT as first-line treatment. The median time from diagnosis to transplantation was 1 (0.1–11.8) year. Conditioning regimen included cyclophosphamide (100–150 mg/kg), fludarabine (150 mg/kg), antithymocyte globulin (ATGAM (100 mg/kg) or thymoglobulin (5–10 mg/kg)), and thoracoabdominal irradiation (2–6 Gy). In some cases, additional medications such as melphalan (140 mg/m²), thiophosphamide (5–10 mg/kg), and rituximab (200 mg/m²) were used. Patients with paroxysmal nocturnal hemoglobinuria (n = 6) received eculizumab at a dose of 600 mg from day –7 to day +14 (every 7 days). Post-transplant GVHD prophylaxis included calcineurin inhibitors. TCRαβ/CD19 depletion was performed using a CliniMACS Plus system (Miltenyi Biotec, Bergish Gladbach, Germany). The median CD34⁺ cell dose in the graft was 10 (2.7–23.0) × 10⁶/kg, and the median TCRαβ⁺ cell dose was 26.6 (0.85–316.00) × 10³/kg.

Results. The cumulative incidence of engraftment was 0,95 (95% confidence interval (CI) 0.9–1.0) with the median time to neutrophil recovery being 13 (9–24) days and to platelet recovery – 12 (7–25) days. Graft rejection occurred in 9 patients, the cumulative incidence of rejection was 0,11 (95% CI 0.06–0.20). Three of these patients underwent successful retransplantation. The cumulative incidence of grade II–III acute GVHD was 0,12 (95% CI 0.05–0.27) in the patients who had undergone unrelated donor HSCT versus 0,42 (95% CI 0.29–0.61) in the haploidentical HSCT recipients (p = 0.003). The cumulative incidence of chronic GVHD was 0,5 (95% CI 0.01–0.20) in the unrelated donor HSCT group and 0,21 (95% CI 0.12–0.38) in the haploidentical HSCT group (p = 0.02). The median follow-up was 6.4 years. Twenty-two (27.5%) patients died. Sixteen of them died of complications after the first HSCT; 4 deaths occurred due to complications associated with repeat HSCT. Two patients died after graft rejection due to infectious complications. The overall survival was 0,79 (95% CI 66–91) in the unrelated donor HSCT group and 0,66 (95% CI 51–81) in the haploidentical donor HSCT group.

Conclusion. The use of TCRαβ/CD19-depleted HSCT from alternative donors ensured high engraftment rates and reduced the incidence of severe GVHD. However, there were no significant improvements in graft rejection or mortality.

Introduction. Primary hemophagocytic lymphohistiocytosis (pHLH) is a group of genetically determined diseases characterized by severe and lightning-fast systemic inflammation, cytopenia, and multi-organ damage with high mortality. The HLH-2004 protocol using high doses of dexamethasone and etoposide is widely used for the treatment of pHLH but it does not always lead to remission of the disease necessary for the next stage of treatment: hematopoietic stem cell transplantation.

Aim: to retrospectively analyze the experience of emapalumab treatment in patients with pHLH.

Materials and methods. A retrospective study was conducted to evaluate the effectiveness and safety of emapalumab in children with pHLH (n = 7) who had been treated at the Center from November 2019 to September 2024. The criterion for inclusion in the study was the diagnosis of pHLH established based on the criteria of the International Society for the Treatment of Histiocytic Disorders (The Histiocyte Society). The severity of the disease was assessed using an adapted H-score with the exclusion of signs of bone marrow hemophagocytosis.

Results. We report the use of the interferon gamma inhibitor emapalumab in seven patients aged 6 to 39 months who had previously been treated according to the HLH-2004 protocol in combination with other immunosuppressants. Three patients received emapalumab at an average initial dose of 1.7 mg/kg and achieved remission at a median of 28 days. The other four patients received emapalumab at an average initial dose of 7.2 mg/kg, with the median time to remission of 14 days (p = 0.0015). A faster and longer-term remission was observed in the patients treated with higher doses of emapalumab.

Conclusion. In this study, we demonstrated the safety and effectiveness of emapalumab treatment in children with refractory pHLH.

Introduction. The implementation of domestically produced antibodies for immunofluorescence staining of blood smears requires a thorough comparative analysis with foreign well-known analogues previously used in diagnosing inherited platelet disorders.

Aim: to conduct a comparative analysis of domestic and foreign antibody kits for immunofluorescence analysis of blood smears used in the diagnosis of the two most common platelet disorders associated with membrane glycoprotein defects: Glanzmann thrombasthenia and Bernard–Soulier syndrome.

Materials and methods. To compare the antibody effectiveness, immunofluorescence analysis of blood smears was carried out for 16 patients with Glanzmann thrombasthenia, 10 patients with Bernard–Soulier syndrome, and 25 healthy volunteers.

Results. In this work, we carried out a qualitative comparison between domestic antibodies to platelet surface glycoproteins: IIbIIIa (CD41) and IbIX (CD42), as well as corresponding fluorescently labeled secondary antibodies and their foreign well-known analogues. It was shown that the domestic antibodies are not inferior to foreign well-known analogues. Clinical trials demonstrated that the expression of glycoprotein IbIX was reduced or completely absent in 10 out of 10 patients with confirmed Bernard–Soulier syndrome. Among 16 patients with confirmed Glanzmann thrombasthenia, only two (13%) did not show decreased or absent expression of glycoprotein IIbIIIa. The stability of blood smear samples stored under various conditions was also evaluated.

Conclusion. A kit of antibodies against platelet glycoproteins (CD41, CD42) was validated. Immunofluorescence analysis of blood smears demonstrated 100% sensitivity for Bernard–Soulier syndrome and 87% sensitivity for Glanzmann thrombasthenia. The samples remained stable for up to 16 weeks at –20°C and at room temperature in vacuum packaging.

Introduction. In Russia, there is currently no standard treatment for acute myeloid leukemia (AML) in children with Down syndrome (DS). The overall survival rates of patients with AML/myelodysplastic syndrome (MDS) and DS in Russia do not exceed 67%. The main problems encountered by these patients are high toxicity and severe infectious complications.

Aim: to conduct a retrospective analysis of treatment outcomes in children with AML/MDS and DS in Russia treated according to different protocols, including those who received non-protocol treatment, and to develop of a uniform treatment protocol with reduced toxicity.

Materials and methods. The analysis included 79 patients, 65 of them with AML and 14 with MDS, who received therapy at 40 Russian clinics from 2018 to 2024. Patient recruitment started in 2018 for the multicenter AML-MRD-2018 protocol study.

Results. Seventy-six patients received specific therapy. A total of 50 (63%) patients underwent treatment according to the ML-DS-2006. Eleven patients (14%) were treated according to the AML-BFM-1998/2004 protocol and 15 (19%) patients received non-protocol treatment according to schemes “7 + 3”, “5 + 2”, low doses of cytarabine. Fifty-eight (75%) patients achieved complete remission. Initially refractory disease was reported in 3 patients (4%), relapses occurred in 6 (8%) patients. One child developed AML six months after the resolution of MDS. The median follow-up was 2 years and 4 months. The overall and event-free survival at 3 years in the patients with AML/MDS and DS were 66% (95% confidence interval 56–79) and 62% (95% confidence interval 52–75), respectively. Mortality among the patients reached 30%; 16 deaths (70%) occurred before remission, 12 (75%) of which were due to infectious complications.

Conclusion. The AML-DS-2025 protocol with a reduced cumulative dose of anthracyclines but an increased total dose of cytarabine, in our opinion, should lead to improved long-term overall and event-free survival rates in children with AML/MDS and DS, as well as to decreased immediate and long-term toxicity.

Introduction. Localized Ewing sarcoma (ES) is a rare aggressive malignant neoplasm coming from small blue round cells, affecting bones and soft tissues, diagnosed most often in adolescents and young adults. ES accounts for 2% of all malignant neoplasms in children and 27% of all primary malignant bone tumors in patients aged 15–29 years. From 2012 to 2024, the musculoskeletal sarcoma research group of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology registered patients in the unified database and coordinated all stages of diagnosis and treatment of children and adolescents with ES in cooperation with regional clinics.

Aim: to analyse the effectiveness of treatment in patients with localized form of ES treated according to the EWING 2008 or Euro Ewing 2012 protocols in the Russian Federation.

Materials and methods. The prospective study included 193 patients with localized ES, registered by the musculoskeletal sarcoma research group at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology between 2012 and 2024. The patients received chemotherapy based on the EWING 2008 protocol and arm B of the Euro Ewing 2012 protocol. Initial patient characteristics, overall (OS) and event-free (EFS) survival were evaluated depending on tumor localization, treatment regimen, extent of surgical resection, pathologic response to treatment.

Results. Treatment according to arm B of the Euro Ewing 2012 protocol proved to be more effective than the previously used chemotherapy according to the EWING 2008 protocol (5-year EFS in the Euro Ewing 2012 and EWING 2008 groups: 74.2 ± 5.1% and 68.0 ± 5.2%, respectively (p = 0.5053), 5-year OS in the Euro Ewing 2012 and EWING 2008 groups: 90.1 ± 3.9% and 83.8 ± 4.1%, respectively (p = 0.3257)). Three-year EFS of patients with localized ES who received high-dose chemotherapy exceeded the results of the Euro Ewing study group: 83.6 ± 8.7% versus 69.0% (95% confidence interval 60.2–76.6), respectively.

Conclusion. The obtained statistical results of OS and EFS are consistent with global data, but we identified several features characteristic of the Russian population.

Introduction. Hereditary spherocytosis is a congenital disease the pathogenesis of which is based on the abnormalities of proteins in the erythrocyte membrane, resulting in impaired membrane permeability and elasticity. During the circulation in the blood flow, the surface to volume ratio of the red blood cell is disturbed, and the erythrocyte acquires a spherical shape. After passing through small capillaries, parts of the membrane, microparticles, are “laced off” from the red blood cell. There is a perception that one of the mechanisms of the development of hypercoagulation leading to thromboembolism in patients with hemolysis is the contribution of procoagulant microparticles. Indeed, the microparticles that have separated from the erythrocyte rapidly become adenosine triphosphate-free, resulting in the loss of asymmetric lipid distribution in the microparticle membrane. Phosphatidylserine, a factor important for blood clotting, is exposed on the outside surface of the microparticle.

Aim: to investigate microparticles in the patients with hereditary spherocytosis.

Materials and methods. Microparticles were assessed using flow cytometry; procoagulant (phosphatidylserine-positive) microparticles were labeled with annexin V, and erythrocyte microparticles were labeled with antibodies to glycophorin A. Coagulation state in the patients was assessed using activated partial thromboplastin time and thrombodynamics.

Results. It has been shown that the number of procoagulant microparticles increases during hemolytic crisis in children with hereditary spherocytosis, which leads to hypercoagulation. It was detected using a global hemostasis assay, thrombodynamics. The increased number of microparticles is one of the possible mechanisms underlying blood clotting disorders. At the same time, the procoagulant properties of microparticles isolated from the blood of the patients with spherocytosis did not differ from those of microparticles isolated from the blood of healthy donors.

Conclusion. Presumably, an increased number of microparticles can be considered a biomarker of cell damage and prothrombotic conditions.

Background. Von Willebrand disease is one of the most common bleeding disorders, with a prevalence ranging from 1 in 100 for asymptomatic disease to 1 in 1000 for severe forms of von Willebrand disease associated with bleeds. The mainstay of therapy for von Willebrand disease is desmopressin and replacement therapy with von Willebrand factor concentrate. One of extremely rare and serious complications of this therapy is the development of an inhibitor to von Willebrand factor.

Clinical case. This article describes the clinical presentation, phenotype, and bleeding manifestations in a female patient with von Willebrand disease with inhibitors, as well as our experience of using emicizumab as off-label therapy.

Conclusion. The development of an inhibitor in patients with von Willebrand disease is an extremely rare complication; this is the first time that we encountered this complication at our center. Physicians should suspect inhibitor development if standard therapy is ineffective or if a patient develops break-through bleedings or allergic reactions to von Willebrand factor concentrate. The off-label use of emicizumab in these patients can reduce spontaneous bleeding episodes and prevent life-threatening bleeding.

Introduction. Immune thrombocytopenia (ITP) is characterized by increased platelet destruction and suboptimal platelet production, which results in reduced platelet counts in peripheral blood and bleeding of varying severity. In children with ITP, remission is often achieved with first-line therapy or even spontaneously. Thrombopoietin receptor agonists and rituximab are considered modern therapies of choice in severe and/or chronic course of the disease, splenectomy is performed less frequently. Despite the favorable prognosis, some patients may exhibit resistance to initial therapy and a small proportion of patients fail to respond to several courses of first- and/or second-line ITP-directed therapies, thus developing refractory ITP. The management of patients with resistant and refractory ITP is a clinical challenge.

Clinical cases. The article presents seven clinical cases of severe ITP of varying duration. The patients aged 1.5 to 17 years received combination therapy due to unsatisfactory therapeutic response in order to prevent severe hemorrhagic complications. The article describes the clinical presentation and different therapeutic approaches, discusses modern possibilities and combined treatment regimens for resistant and refractory ITP in children.

Conclusion. Overall, current studies of pathogenesis and the development of guidelines for managing ITP patients aim to optimize treatment, particularly for resistant, refractory, severe persistent and chronic forms of the disease, reduce the risk of bleeding, increase the likelihood of achieving long-term remission, and improve the quality of life of patients and their families.

Activated platelets are divided into two subpopulations: proaggregatory and procoagulant. The procoagulant subpopulation of platelets began to be actively studied about 20 years ago. This type of platelets has a large number of procoagulant proteins on its surface. It is already known what mechanisms are responsible for the distribution of platelets into subpopulations and how this process can be influenced. At the moment, this knowledge is not used in medical practice. There are reports in the literature on the relationship between the number of procoagulant platelets and some pathological conditions of the body, such as heart attacks, strokes, etc. However, accurate information on the contribution of procoagulant platelets to the physiology of thrombus formation is insufficient. This review collects known literary data on the interaction of the procoagulant subpopulation of platelets with the blood coagulation and fibrinolysis systems. The literature analysis showed that the relationship of the procoagulant subpopulation with fibrinolysis has not been sufficiently studied. Procoagulant platelets have both lysis-promoting and lysis-protecting proteins. The quantitative contribution of this subpopulation to fibrinolysis is unknown. Thus, further study of the physiology of procoagulant platelets is necessary to develop new therapeutic approaches using the properties of this subpopulation.

Clonal hematopoiesis is a condition that develops as a result of the accumulation of somatic mutations in hematopoietic stem cells, leading to the formation of clones with a selective advantage. Initially considered a marker of aging, it is now recognized as an important risk factor for the development of both hematological and non-hematological diseases. This article systematizes current scientific understanding of the key molecular mechanisms underlying the initiation and progression of clonal hematopoiesis, details its main genetic determinants, and analyzes the pathogenetic role of this phenomenon in the development of congenital and acquired bone marrow failure syndromes. Special attention is paid to elucidating the complex pathophysiological relationships between clonal hematopoiesis and oncological diseases, particularly the formation and progression of solid tumors. A deep understanding of the dynamic changes characterizing the evolution of clonal hematopoiesis is of fundamental importance for improving approaches to early diagnosis, accurate prediction of individual risk of malignant transformation, and the development of personalized therapeutic strategies for patients suffering from various forms of bone marrow pathology and oncological diseases.