Introduction. Primary cutaneous B-cell lymphomas (PCBCL) are a rare group of lymphoproliferative diseases with diverse clinical manifestations, differential diagnostic algorithms, treatment options, and prognoses.

Aim: to characterize patients with PCBCL according to clinical, pathomorphological and cytogenetic parameters.

Materials and methods. Data from 57 patients with PCBCL, who had been observed and/or treated between January 2011 and December 2023, were retrospectively analyzed and included in the study conducted by the Russian Group for the Study of Cutaneous Lymphomas.

Results. The most common subtype was primary cutaneous diffuse large B-cell lymphoma (PC-DLBCL) (40 %), while primary cutaneous marginal zone lymphoma (PC-MZL) and primary cutaneous follicle center lymphoma (PC-FCL) accounted for 32 % and 28 %, respectively. The long-term overall survival rate of PCBCL was 90 % in the entire group and indicates a favorable prognosis for PCBCL. At the time of diagnosis verifi cation, 42 out of 55 patients had indications for therapy (33 % in indolent cases, 100 % in PCDLBCL). Of these, 89 % had a complete response after the fi rst line (PCFCL — 93 %, PCMZL — 94 %, PCDLBCL — 78 %). For patients with PCDLBCL, effi cacy was demonstrated when using systemic chemotherapy according to the mNHL BFM-90 protocol: 5-year disease-free survival (DFS) and event-free survival (EFS) were 83 % and 76 %, respectively. For PCFCL and PCMZL, effi cacy was demonstrated with surgical resection and radiation therapy (5-year DFS and EFS were 71 % and 67 %, respectively). The analysis of the identifi cation of factors of the unfavorable course of the disease revealed an increase in the risk of recurrence/ progression by 40 % with lower limb damage in all PCBCL variants.

Conclusion. For PCFCL and PCMZL, radiation therapy demonstrated the highest therapeutic effi cacy. In patients with PCDLBCL, various chemotherapy regimens are indicated at the stage of diagnosis verifi cation, with high-dose chemotherapy being the most effective. Localization of the pathological process in the lower limbs is associated with an increased risk of relapse across all PCBCL subtypes.

Introduction. Primary testicular diffuse large B-cell lymphoma (PT-DLBCL) is characterized by an aggressive course and a high relapse rate when using standard therapy protocols. A feature of PT-DLBCL is its high tropism for central nervous system damage.

Aim: to compare the treatment outcomes of patients with PT-DLBCL treated with known protocols and according to the “PTL2022” protocol.

Materials and Methods. From 2006 to 2025, 54 patients with PT-DLBCL were included in the analysis: 12 patients in the prospective group and 42 patients in the retrospective control group.

Results. CNS involvement at the onset of PT-DLBCL in the prospective group was present in 60 % of patients, in the retrospective group the frequency of CNS involvement is unknown. In the entire group of all 54 patients with PT-DLBCL, event-free survival (EFS) and overall survival (OS) were 20 % and 29 %, respectively. In the retrospective group, EFS was 17%, in the prospective group 90 %, OS — 28 % and 90 %, respectively.

Conclusion. The “PTL-2022” protocol is reproducible, effective and safe in different age groups of patients. An improvement of treatment outcomes with the “PTL-2022” protocol was established in the high-risk group.

Introduction. Cytomegalovirus retinitis (CMVR) is a necrotizing disease of the retina that can cause irreversible blindness. An increase in the number of CMVR episodes increases the likelihood of developing irreversible blindness. Reducing the risk of CMVR recurrence will improve the effectiveness of visual rehabilitation for this category of patients. Aim: To study the patterns and risk factors for the development of CMVR recurrence in children who are recipients of hematopoietic stem cells.

Materials and methods. The study included 37 patients aged 0 to 21 years (62 eyes) who had undergone CMVR and hematopoietic stem cell transplantation and received a series of intravitreal injections (IVI) of antiviral drugs. CMVR recurrences occurred in seven patients. In 3 patients, there was a recurrence in 1 eye, in 4 — in both eyes. Of the 62 eyes, 51 had no recurrences, 6 had one recurrence, and 5 had more than one recurrence. A recurrence was diagnosed in 23 out of 81 episodes. Remission was considered achieved when the absence of cytomegalovirus DNA was confi rmed in a sample of aqueous humor taken from the anterior chamber of the eye and/or upon complete healing of CMVR lesions as determined by ophthalmoscopy.

Results. Discontinuation of IV antiviral drugs based on negative aqueous humor PCR results reduces the likelihood of recurrence by more than 16 times compared to a decision based on ophthalmoscopic data (p-value = 0.011) and by more than 2 times compared with non-zero PCR results.

Conclusion. The recurrent nature of the course of CMVR is associated with the replication of virus copies inside the eye. Elimination of copies of the virus from the intraocular fl uid reduces the likelihood of developing a CMVR recurrence.

Introduction. In the Russian Federation, there is insuffi cient data on approaches to the treatment of polycythemia vera (PV) and myelofi brosis (MF). There is also a lack of information on the assessment of treatment effectiveness in routine clinical practice.

Aim: to study treatment approaches for patients with MF (primary myelofi brosis (PMF), post-polycythemic myelofi brosis (PPMF), post-thrombocythemic myelofi brosis (PTMF)) and PV in routine clinical practice.

Materials and methods. A multicenter, non-interventional, prospective observational study included 2005 patients from 49 centers: PV — 1019 (50.8 %), MF — 986 (49.2 %) patients. Gender, age, diagnosis, disease duration, mutation status of the JAK2 V617F gene, risk groups, and quality of life were analyzed.

Results. The median age of patients with PV was 57 years, MF — 55 years. In one third of PV patients, a histological examination of the bone marrow trepan biopsy was not performed; in MF, trepanobiopsy was not conducted in less than 10 % of cases. When assessing the risk of thrombotic complications in PV, only 9.0 % of patients were classifi ed as high-risk, yet thrombotic events were reported in 13.7 % of cases. According to the IPSS index, 39.8 % of MF patients were classifi ed as intermediate-2 and high-risk, while 27.0 % were classifi ed by the DIPSS index. In more than 80 % of cases, patients receivedhydroxycarabamide. 76.9 % of MF patients responded to ruxolitinib therapy for a period of 60 months, but only 30 MF patients received it as fi rst-line therapy. Ruxolitinib was used as second-line therapy in 183 (18.6 %) MF patients and 54 (5.3 %) PV patients in the entire study group. Analysis of survival in over 2,000 patients allowed for the evaluation of overall survival (OS) and event-free survival (EFS), which are close to epidemiological estimates, indicating the persistent complexity of treating these patients. The proportion of MF patients with progressive disease was comparable to the proportion of patients who responded to therapy for all drugs except ruxolitinib. The use of ruxolitinib made it possible to achieve remission in most patients.

Conclusion. The study characterized treatment outcomes and clinical-demographic features of patients with MPN. Discrepancies exist between real-world clinical practice and the diagnostic and therapeutic algorithms presented in the clinical guidelines.

Introduction. Thrombosis and bleeding are frequent complications of essential thrombocythemia (ET) and polycythemia vera (PV). Platelet morphofunctional abnormalities in these disorders are poorly understood.

Aim: To study the morphofunctional characteristics of platelets in ET and PV.

Materials and methods. The study included 39 patients under 18 years of age with an established diagnosis of ET (n = 26) and PV (n = 13). The control group consisted of 40 healthy children. The manifestations of ischemic and hemorrhagic symptoms, hepato-/splenomegaly were evaluated. Platelets were studied using fl ow cytometry (FC) with activation by a mixture of thrombin and collagen analogues; the activity of the Willebrand factor was measured.

Results. Depending on the presence and type of driver mutation, all patients were divided into 3 groups. Group 1 included 16 patients with triple negative (TN) form of ET. Group 2 included 15 patients with JAK2 driver mutation and diagnoses of PV or ET. The third group included 8 patients with CALR driver mutation and a diagnosis of ET. The platelet count was higher in the TN group when compared to the JAK2 group (p = 0.005) and did not differ between the TN and CALR groups (p = 0.98). Hepatomegaly was observed in 36 % of patients, splenomegaly in 56 %. Symptoms of ischemia and/or bleeding were observed in 54 % of patients. Acquired von Willebrand disease syndrome developed in 64 % of patients. According to the results of FC, the size of non-activated platelets was reduced in all groups when compared to the control group (p ≤ 0.01). The reduction in platelet size upon activation was signifi cantly attenuated in JAK2 and CALR (p ≤ 0.0015). Platelet granularity was reduced in TN and CALR groups (p ≤ 0.01) when compared to the control. Morphological abnormalities of platelets, in the form of an increase in their granularity relative to cell size, were detected in 58 % of patients. The decrease in the amount of CD42b on the platelet membrane, due to Shedding and internalization, was signifi cantly attenuated in all patient groups (p ≤ 0.01). The externalization of CD61 on the platelet membrane surface upon activation was attenuated in all groups (p ≤ 0.02). In the JAK2 and CALR groups, the volume/number of platelet dense granules were signifi cantly reduced at rest (p ≤0.02), and upon activation, dense granule degranulation was attenuated (p < 0.001) when compared to the control. Conclusion. Common morphofunctional platelet abnormalities (reduced size, abnormalities in CD42b and CD61 expression) were identifi ed in children and adolescents with ET/PV, independent of the genetic cause.>< 0.001) when compared to the control.

Conclusion. Common morphofunctional platelet abnormalities (reduced size, abnormalities in CD42b and CD61 expression) were identifi ed in children and adolescents with ET/PV, independent of the genetic cause.

Introduction. The prevalence of blood-borne infections in the Russia remains high. Between 2016–2023, additional safety measures and requirements were introduced for the examination of donor blood, such as molecular screening for pathogens and additional HBV markers testing.

Aim: to analyze the frequency of detection of blood-borne infections in blood donors against the background of the epidemiological situation in the Russian Federation.

Materials and methods. Data from National Report (form No. 64) on the production, storage, transportation and clinical use of donor blood and data from the transfusion information system of the National Medical Research Center for Hematology, Russia, were used.

Results. The implementation of new safety measures carried the risk of reducing the number of donors, but fortunately, this did not happen. By 2020, the prevalence of socially signifi cant infections among donors in the Russian Federation decreased from 18,064 cases to 5,596 cases. However, there was an increase in 2021. This trend correlates with the dynamics of morbidity rates among the population of the Russian Federation. The approach to the registration and control of blood-borne infections for donors differs from that of the general population. For example, HIV-vulnerable population groups are recommended only for voluntary testing, thus, the true incidence rate of HIV in Russia may exceed the offi cial data. A similar problem is observed with viral hepatitis. HBV markers were found in donors of blood and its components more often than other infectious markers. However, among the population of the Russian Federation, the incidence rate of HBV is lower than that of HIV infection (9 versus 40 cases per 100,000 population, respectively).

Conclusion. The prevalence of blood-borne infections among the population of the Russian Federation creates a threat of infected people entering the donor population. Surveillance and control of viral hepatitis B and C requires improvement.

Introduction. The issues of public participation in voluntary non-remunerated blood donation are among the priority areas of state policy in the fi eld of healthcare. Despite signifi cant progress, contemporary demographic, geopolitical, and other challenges underscore the relevance of research in this area, which has not yet been widely explored in Russia.

Aim: to identify the characteristics of Russians’ participation in blood donation.

Materials and methods. The study employs an original sociological methodology, tested through a mass survey of blood donors (n = 402) conducted from July to September 2024 at the Vologda Regional Blood Transfusion Station No. 1.

Results. Blood donors were found to be a highly heterogeneous community, with motivation for participation in blood donation varying signifi cantly depending on socio-demographic factors and donation frequency. The latter factor proved to be one of the most important in developing effective interaction strategies between blood services and the population. Differences between fi rst-time and regular donors were revealed in their willingness to continue donating, awareness of the need for specifi c blood types, satisfaction with their visits to the blood transfusion station (BTS), etc. These factors should be taken into account in order to enhance voluntary non-remunerated blood donation.

Conclusion. The survey results provided a basis for identifying promising directions for improving donor information systems and the BTS operations. Among the main measures: implementing a fl exible appointment system for blood donation, reducing wait times for an appointment with a specialist and the donation procedure, increasing donor awareness, improving the work of the ”donor traffi c light“ system, sending mobile teams to for on-site workplace donations, placing outdoor donation advertisements and providing reserved parking for donors.

Introduction. Anal fi stulas (AF) can be both an independent source of infection and the cause of perianal abscess recurrence. The use of sphincter-preserving plastic surgical methods for the elimination of AF in patients with hematologic malignancies is an insuffi ciently studied issue.

Aim: To demonstrate the possibility of using plastic surgical methods for the elimination of rectovaginal and anal fi stulas in hematological patients.

Materials and methods. Between 2022 and 2024, 5 patients aged 36 to 56 years were operated on for complex anal and rectovaginal fi stulas; of these, 3 patients had acute myeloblastic leukemia (AML), 1 had non-Hodgkin’s lymphoma, and one patient had immune thrombocytopenia. In one case, elimination of a rectovaginal fi stula was performed using a split vaginal-rectal fl ap; in the rest — the anal fi stulas were eliminated using a displaced lateral fl ap. The follow-up period ranged from 8 to 28 months.

Results. Elimination of the AF was achieved in 4 out of 5 patients. On the 2nd day after surgery, 1 patient developed thrombosis of hemorrhoids in the area of the displaced fl ap, and on the 10th day, a recurrence of the fi stula was detected. Signs of 1st degree anal insuffi ciency were diagnosed in two patients who had previously undergone anal surgery. Treatment for hematologic malignancies was continued after surgery for two patients, one of whom underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), while the other underwent induction of a second remission due to a AML relapse.

Conclusion. Given the minimal surgical trauma and low complication rate, fi stula repair using displaced fl aps can be used in hematological patients. If rehabilitation timelines are observed, it is possible to resume antitumor therapy, including performing allo-HSCT.

Introduction. Cell free DNA (cfDNA), being an easily accessible and promising clinical material, as previously shown in obstetrics and general oncology, is of particular interest in hematology. In recent years, the study of plasma cfDNA in hematological diseases has been gaining increasing interest among researchers and physicians. To date, a signifi cant amount of data cfDNA and tumor cfDNA (cftDNA) in patients with diseases of the blood system has been accumulated in the world literature.

Aim: to study the literature data on the cfDNA in aggressive B-cell lymphomas and Hodgkin’s lymphoma (HL).

Main fi ndings. The review presents the literature data on the study of cfDNA, the possibilities and limitations of using various methods of studying cfDNA in patients with aggressive B-cell lymphomas and HL.

Introduction. Chimeric Antigen Receptor T-cell (CAR-T) therapy is an effective treatment for relapsed/refractory (R/R) lymphoproliferative diseases. Hemostasis disorders can complicate CAR T-cell therapy.

Aim: to examine hemostatic disorders arising during CAR T-cell therapy.

Main fi ndings. CAR T-cell therapy leads to disorders of both the platelet and plasma components of hemostasis. CAR T-associated thrombocytopenia can be early (from day 0 to +30), late (from day 31 to 90), or persistent (after day +90). Treatment involves both platelet concentrate transfusions and, in some cases, thrombopoietin receptor agonists. Coagulation disorders manifest as both hemorrhagic syndrome and thromboembolic complications. Guidelines for hemostatic and anticoagulant therapy have not yet been established.