The development of National clinical guidelines on diagnosis and treatment of Ph-negative myeloproliferative neoplasms provides the knowledge basis for decision making in diagnosis, therapy, prevention, and rehabilitation in compliance with evidence-based medicine principles in order to ensure appropriate medical care in a particular clinical setting. The clinical guidelines underly the choice of optimal methods of diagnosis, therapy, prevention, and rehabilitation as part of a patient’s medical care, the development of criteria for the assessment of medical care quality, medical care standards, medical care procedures, setting standards on equipment and management of diagnostic and therapeutic procedures, and provision of continuous medical education and advanced training for healthcare professionals. In 2013, a working group was formed to develop and formulate clinical guidelines on the treatment of myeloproliferative neoplasms. These guidelines were first published in 2014, afterwards they were revised and republished. The dynamic development of current hematology presupposes constant updating of knowledge and implementation of new diagnosis and treatment methods in clinical practice. In this context, clinical guidelines present a dynamic document to be continuously amended, expanded, and updated in accordance with scientific findings and new requirements of specialists who are directly involved in treatment activities. The present edition is an upgraded version of clinical guidelines with updated information on classification, diagnosis, prognosis, current methods of therapy, and their efficacy and tolerability assessment. The guidelines are intended for oncologists, hematologists, healthcare executives, and medical students.

Aim. To compare the efficacy of mobilization regimens (MR) differing in their composition and intensity, with the purpose of defining the criteria to personalize the choice of MR based on clinical and hematological characteristics of multiple myeloma (MM) patients. Materials & Methods. A retrospective analysis of the autologous hematopoietic stem cell (HSC) mobilization and autograft harvesting results was performed in 177 patients with newly diagnosed MM. The patients were divided into 4 groups. Group 1 included 62 patients with the median age of 53 years who were treated with single injection of cyclophosphamide (CF) dose 3 g/m2 as MR. Group 2 consisted of 71 patients with the median age of 58 years who received vinorelbine 35 mg/m2. Granulocyte colony-stimulating factor (G-CSF) as a monoregimen was administered to group 3 consisting of 33 patients with the median age of 55 years. Group 4 included 11 patients with the median age of 57 years who received G-CSF enhanced by plerixafor administration. G-CSF 10 µg/kg was used as MR. In all chemomobilization cases, daily G-CSF 10 µg/kg started on Day 4 from the administration of the chemotherapy drug prescribed as MR. Results. In the analyzed groups, the median time from MR start to the first leukocyte apheresis session was 11, 8, 5, and 5 days, respectively. On the first leukocyte apheresis day, the median CD34+ cell collection in group 3 was significantly lower than in groups 1, 2, and 4: 2.2 × 106/kg vs. 3.79 × 106/kg, 7.22 × 106/kg, and 3.9 × 106/kg, respectively. The total CD34+ cell collection after two leukocyte apheresis sessions was also the lowest in group 3 compared with groups 1, 2, and 4: 3.22 × 106/kg vs. 5.2 × 106/kg, 4.95 × 106/kg, and 7.5 × 106/kg, respectively. In the analyzed groups, the rate of mobilization with CD34+ cell collection < 2.0 × 106/kg was 6.5 %, 5.6 %, 18.2 %, and 9.1 %. The evaluation of the results in all patients showed a direct correlation of CD34+ cell collection with lenalidomide administered before autologous HSC mobilization. A significant difference in CD34+ cell collection in lenalidomide recipients vs. non-recipients was reported when vinorelbine as MR and G-CSF as monoregimen (р = 0.001 and р = 0.022, respectively) were used. No significant differences were observed either with CF or G-CSF combined with plerixafor treatment. Conclusion. Based on the findings, age of a MM patient, comorbidities, and prior lenalidomide administration can be regarded as key criteria for choosing one of 4 MRs.

A cautious attitude towards patients with multiple myeloma (MM) over 60 years of age as potential candidates for autologous hematopoietic stem cell transplantation (AutoHSCT) is often due to low somatic status and/or the presence of comorbidities that increase the likelihood of developing severe complications after high-dose chemotherapy. Improving the somatic condition, resolving comorbidities, and improving the quality of life in the case of effective therapy expands the possibilities for performing AutoHSCT in older people

Aim. To conduct an interim outcome analysis of conditioning regimens with carfilzomib or thiotepa compared to standard melphalan 200 mg/m2 regimen in multiple myeloma (MM) patients with single autologous hematopoietic stem cell transplantation (auto-HSCT). Materials & Methods. The retrospective analysis focused on outcomes of 67 single auto-HSCTs performed from 2017 to 2021. Responses as well as progression-free (PFS) and overall survival (OS) rates were compared in MM patients per IWMG criteria in pre- and post-transplant periods. Three conditioning regimens were assigned: melphalan 200 mg/m2 (Mel200), melphalan/carfilzomib combination (Mel/Karfil), and melphalan/thiotepa combination (Mel/Thio). In an additional cohort of 12 MM patients, next-generation sequencing assay was used to detect inherited and somatic mutations associated with proteasome inhibitor efficacy. For this purpose, DNA of peripheral blood lymphocytes and bone marrow plasma cells were examined. Results. PFS medians were comparable in MM patients treated with Mel200 (n = 40) and Mel/Karfil (n = 10) conditioning regimens, they were 32 and 23 months, respectively (p = 0.241). In these cohorts, OS median was not reached, and the curves showed no significant differences (p = 0.050). Out of 10 MM patients treated with Mel/Karfil, six received melphalan 140 mg/m2, the remaining 4 patients received 200 mg/m2. Complete response (CR) rate in the Mel200 and Mel/Karfil groups increased two-fold after auto-HSCT: from 35.5 % to 74.2 % and from 25.0 % to 50.0 %, respectively. The worst PFS and OS medians were in the Mel/Thio group, i.e., 12 and 17 months, respectively, and CR rate after auto-HSCT remained unchanged. The best PFS was associated with CR rather than very good partial or partial response after auto-HSCT, they were 48, 21, and 23 months, respectively (p = 0.001). Exome sequencing of DNA of peripheral blood lymphocytes and bone marrow plasma cells revealed polymorphic variants in the genes associated with chemotherapy response. Conclusion. The outcomes of Mel/Karfil, the regimen containing the reduced dose of melphalan 140 mg/m2, and the statistical comparability with the Mel200 regimen suggest that this combination can be effective in the treatment of MM patients with impaired renal function, which still needs to be further confirmed. No advantage of the combined conditioning regimen over the standard one can be accounted for by the loss of plasma cell sensitivity to proteasome inhibitors. The obtained data provide ground for modifying the study protocol with a particular focus on evaluating the efficacy and safety of conditioning regimen Mel/Karfil with melphalan 200 mg/m2 depending on biologic phenotype of plasma cell.

Topic: 5. Chronic lymphocytic leukemia and related disorders - Biology & Translational Research Background: The course of several lymphoproliferative diseases, especially chronic lymphocytic leukemia (CLL) is often accompanied by immune disorders. Such patients are characterized by pathological activation of immunity with a change in autotolerance and the development of autoimmune disorders. Among the latter, the most famous common are hemolytic anemia, autoimmune thrombocytopenia, but there is very little work there are quite rare articles devoted to neutropenia. To solve the question of the involvement of immune mechanisms in the development of neutropenia and anemia, it is necessary to determine autoantibodies. Aims: Assessment of the frequency of occurrence of autoantibodies to neutrophil and erythrocyte antigens in patients with chronic lymphoproliferative diseases. Methods: Blood samples of 316 patients with CLD: chronic lymphocytic leukemia, hairy cell leukemia, Hodgkin’s lymphomas, non-Hodgkin’s lymphomas, multiple myeloma patients were included in the study. The mean age of patients was 64 years (range, 22 to 84). Granulocyte-specific autoantibodies were detected by the granulocyte immunofluorescence test (GIFT Flow Cytometry). The determination of classes of antibodies directed against RBCs was carried out in a direct Coombs reaction using a gel system DiaMed-ID. Results: The frequency of detection of autoantibodies to neutrophil antigens was 3.4%. Thus, in patients with multiple myeloma, autoantibodies occurred in 2.5% of cases, chronic lymphoid leukemia - in 4.3%, hairy cell leukemia - in 20.0%, Hodgkin’s lymphoma - in 9.1%, non-Hodgkin’s B-cell lymphoma - in 1.5%. The frequency of detection of autoantibodies to erythrocyte antigens was 21.7%. Autoantibodies to erythrocyte antigens were detected in 19.1% of patients with multiple myeloma, in 39.1% of patients with chronic lymphocytic leukemia, in 16.9% of patients with non-Hodgkin lymphoma and in 4.7% of patients with Hodgkin lymphoma. One patient with Hodgkin lymphoma was diagnosed with autoantibodies to both neutrophils and red blood cells. This patient was characterized by a severe course of the disease and the absence of clinical and cytogenetic remission. Changes in autotolerance and the production of autoantibodies in patients with HPPA may be associated with various mechanisms, including impaired T lymphocyte function and pathological presentation of autoantigens by tumor B cells, as well as the secretion of inhibitory cytokines by tumor B cells that alter immune tolerance, enhancing the survival of autoreactive clones. Monotherapy with alkylating antitumor drugs and analogues of purine bases also increases the risk of developing autoimmune neutropenia. Summary/Conclusion: Autoantibodies to neutrophil antigens were more common in patients with hairy cell leukemia and Hodgkin lymphoma. The lowest percentage of antibody detection was observed in non-Hodgkin lymphomas. While autoantibodies to red blood cells were more often detected in patients with CLL and NHL. Keywords: Lymphoproliferative disorder, Autoantibody

Aim. To compare toxicity and efficacy of high-dose melphalan chemotherapy with subsequent autologous hematopoietic stem cell transplantation (auto-HSCT) in multiple myeloma (MM) patients aged under and over 60 years. Materials & Methods. The retrospective analysis was conducted on the data of 107 MM patients, 78 of them were aged under 60 years (median 54 years), and 29 of them were aged 61 years and older (median 63 years). All patients received auto-HSCT in the period of 2017–2022. Single and tandem auto-HSCT were performed in 92 and 15 patients, respectively. Patients with tandem auto-HSCT (n = 15), lost to follow-up patients (n = 8), and patients who died during early post-transplant period (n = 4) were excluded from survival analysis. Survival rates were calculated based on the date of auto-HSCT. Results. A comparative evaluation of the results in two age groups showed a significant difference in the number of patients treated with ixazomib during the induction period (р = 0.019) and cyclophosphamide 3 g/m2 as part of auto-HSC mobilization (р = 0.014), as well as 200 or 140 mg/m2 melphalan as part of conditioning regimen (р = 0.039 and р = 0.009, respectively). With a follow-up median of 13 months (range 1–57 months), the median progression-free survival in the groups ≤ 60 years vs. > 60 years was 32 and 47 months, respectively (hazard ratio [HR] 0.688; 95% confidence interval [95% CI] 0.270–1.754; p = 0.704). The median overall survival in patients aged under 60 years appeared to be 57 months, it was not reached in patients aged 61 years and older (HR 0.689; 95% CI 0.169–2.803; р = 0.577). Conclusion. The results of the study suggest that all newly diagnosed MM patients aged under 70 years should be regarded as being eligible for auto-HSCT.

This paper is a case report of a patient with newly diagnosed multiple myeloma (MM) who underwent exome sequencing of peripheral blood lymphocytes and CD138+ tumor plasma cells prior to therapy. This patient showed some inherited genetic variants which are associated with underlying risk for MM. This patient’s genotype was reported to have some variants in the DNA repair genes, including inherited mutations in the RFDW3 and TP53 genes. They are involved in the maintenance of genome stability and accumulation rate of somatic mutations, including structural rearrangements and chromosome aberrations. A large number of structural variations and mutational signature ID6 in the tumor genetic material point to the disruption of DNA damage repair. The tumor cell exome analysis yielded a profile of somatic mutations, also the mutations in the genes previously associated with MM, as well as a functional significance of the detected abnormalities. Somatic mutations also included damaging mutations and highly significant mutations in the other tumor-associated genes, such as ASCC3, TET3, and CHD1, as well as in the antimicrobial peptide-coding genes CAMP and HTN3. With the exception of an extra copy of 1q arm in the tumor plasma cell genome, the patient showed no genetic risk factors associated with poor prognosis of the disease. Based on literature, inherited (ABCB1 mutations) and somatic (trisomy 3) variations detected in the patient’s genetic material can be characterized as positive prognostic factors in MM.

Topic: 4. Acute myeloid leukemia - Clinical Background: AML is heterogeneous disease with much fewer treatment options. 7 + 3 and different high dose ARA-C combinations are still the mainstream approaches for patients that fit the intensive therapy. New treatment with AZA+ven has emerged for the elderly or unfit AML pts, but there are few publications about its efficacy as the first line treatment in youngs pts with de novo AML, especially AML with myelodysplasia related changes (MRC-AML). The question whether allo-HSCT is necessary in CR1 if MRD-negativity was achieved after the 1st induction course and sustains afterwards still remains open Aims: To define in a randomized fashion the role of allo-HSCT in AML pts who achieved MRD-negative CR after the first 7 + 3 cycle disregard of ELN risk group (excluding MRC-AML and inv16) Methods: In Feb 2021 Russian Leukemia study group has initiated a multicenter prospective clinical trial registered on ClinTrialGov NCT05339204. ELN 2017 and WHO 2016 classification were used for patients’ stratification. Induction and consolidation treatment was planned to be different for pts with MRC-AML (low intensive: Aza-Ven or Aza-LDIda-LDAra-C) and for all other AML types (two 7 + 3 (dauno 60m2) and two FLAG cycles, followed by 6 maintenance 5 + 5 cycles with ARA-C and 6MP). Cytogenetic and molecular testings were done and MRD was also monitored by MFC in a centralized lab. Pts with molecular markers were followed in parallel by PCR. MRC-AML pts (group C) were all candidates for early allo-HSCT (within 4 cycles). Inv16 pts (group A) were considered as candidates for allo-HSCT only if MRD persisted after the 4th cycle at high levels or was increasing. All other AML pts were included in Group B, and those who achieved MRD-negative CR after the first 7 + 3 cycle were randomized to early allo-HSCT (within 4 cycles) or no allo-HSCT (or postponed allo-HSCT in case of MRD-conversion) Results: 104 pts from 11 Centers were enrolled from Feb 2021 to Nov 2022. 9 pts (inv16 AML) have formed Group A (8,6%), 73 – Group B (70,3%), 22 MRC-AML pts – Group C (21,1%). 84 pts were eligible for evaluation of min 2 inductions. Total CR rate was 76,2% (Group A – 100%, B – 75,4%, C – 66,7%), 60-day mortality - 10,7% (A-0%, B – 15,8%, C – 11,1%), refractory AML – 10,7% (A-0%, B – 8,8%, C – 22,2%). In group B among 48 CR pts 43 achieved CR after the 1st ind. cycle and 33 of them (76,7%) were MRD-negative. So 29 of 33 were randomized: 14 - to early allo-HSCT (7 were performed with a median time from CR to allo-HSCT 6,3 mо), 15 – to postponed allo-HSCT. All 10 pts that were MRD-positive after the 1st 7 + 3 were directed to allo-HSCT, and 5 were transplanted with a Me time 5,5 mo. All CR pts from Group C were allocated to allo-HSCT (70% were already transplanted with a Me time from CR to allo-HSCT=2,9 mo). No one was transplanted from group A, and one has a late relapse and was transplanted in 2nd CR. 1-year OS for the whole cohort of pts was 70%, DFS – 73%. It’s too early to compare randomized groups. 1-y OS for Gr. A =100%, Group B - 74%, Group C - 50%. 1-y DFS for Group A – 100%, for Gr. B - 68%, for Gr. C - 75% Summary/Conclusion: To our knowledge our trial is the only one investigating in a randomized fashion the role of allo-HSCT in 1st CR for AML pts who are MRD-negative after the 1st induction disregard ELN 2017 risk groups.The first results of a prospective clinical trial have demonstrated that it took a long time from CR achievement to allo-HSCT in the majority of AML pts - 5,5-6,3 mo. MRC-AML pts reached allo-HSCT somewhat earlier – 2,9 mo, with 75% 1-year DFS. Further follow-up will answer the posed questionKeywords: HSCT, Acute myeloid leukemia, Minimal residual disease (MRD)

Aim. To compare the expression levels of the WNT family genes in mesenchymal stromal cells (MSC) of the bone marrow (BM) hematopoietic niche in multiple myeloma (MM) patients vs. healthy donors. Materials & Methods. The study enrolled 12 MM patients aged 49–71 years (the median age 61 years) after standard induction bortezomib therapy. The treatment efficacy was assessed in accordance with the criteria of International Myeloma Working Group (IMWG). Patients were stratified in groups with complete and partial response (CPR; group 1, n = 9) and no response (group 2, n = 3). Besides, a group of primary untreated patients was formed (n = 2). The control group included healthy donors of BM (n = 3). The levels of the WNT and CTNNB1 gene expression were assessed by real-time PCR on cDNA isolated from MSC. Results. In the group of 2 primary patients, two genes (WNT2B and WNT9B) considerably differed in the degree of expression. In non-responders (n = 3), the WNT2B expression could not be determined, whereas the WNT15 expression appeared to be increased. In group CPR (n = 9), mRNA level of the WNT5A gene increased after therapy, whereas the WNT3A gene expression returned to the normal level. The WNT7B gene transcription level did not differ in the control and comparison groups. In group CPR, a significant expression increase in the β-catenin-coding CTNNB1 gene was detected. Conclusion. The differences identified in the expression of the WNT2B, WNT9B, and CTNNB1 genes suggest the possibility of their use as prognostic molecular markers in MM.

Topic: 22. Stem cell transplantation - Clinical Background: Preparation of an autograft involves obtaining at least 2x106 CD34+ cells/kg of the patient’s weight. The choice of the optimal mobilization regimen for each patient with multiple myeloma (MM) involves an assessment of the patient’s condition, disease status, volume and nature of previous therapy. For mobilization, combinations of cytostatic drugs with granulocyte colony-stimulating factor (G-CSF), G-CSF alone or in combination with plerixaphor are used. An assumption was made about the influence of the content of individual subsets of lymphocytes in the autograft on the course of MM in the post-transplant period. Aims: To evaluate the effect of mobilization modes on the composition of lymphoid subsets in the autograft of MM patients. Methods: Individual subsets of lymphocytes in the apheresis products of 25 MM patients were analyzed. G-CSF in mono mode (group 1, n=12), vinorelbine in combination with G-CSF (group 2, n=9) and cyclophosphamide at a dose of 3 g/m2 in combination with G-CSF (group 3, n=4) were used as mobilization regimens. Autologous hematopoietic stem cell transplantation (AutoHSCT) was performed in 12, 7 and 4 patients, respectively. For pre-transplant preparation, the Mel200, Mel140 regimens and the combination of melphalan with carfilzomib were used in 7/3/2, 3/0/4 and 4/0/0 patients, respectively. All patients received G-CSF in the post-transplant period, except for 1 patient in group 1. Results: A significant difference was found in the content of CD3+ cells, the percentage of which was significantly higher when using cyclophosphamide compared to G-CSF in mono mode: 91.4% vs 77.6%; p=0.029. On the contrary, the content of CD3-CD8+ cells was the lowest with the appointment of cyclophosphamide compared with the other two modes of mobilization: 0.3% vs 3.6% with G-CSF alone; p=0.045 and 0.3% vs 1.5% for vinorelbine; p=0.016. There were also significantly fewer NK cells (CD3-CD16+): 1.65% vs 10.4% with G-CSF mono. Engraftment of leukocytes and platelets in the studied groups was recorded on days 12 (9–26), 11 (10–17), 12.5 (11–16) and on days 18 (13–28), 16 (13–20), 16.5 (12–22), respectively. Six (50%), 3 (42.9%) and 2 (50%) patients in the studied groups, respectively, required transfusion of donor red blood cells. All patients received transfusions of platelet concentrate, the median number of doses in the groups was 5 (1–16), 4 (2–7) and 5 (2–7), respectively. Before AutoHSCT, all patients received bortezomib, carfilzomib – 3 (25%), 5 (55.6%) and 2 (50%) patients, respectively, lenalidomide – 1 (8.3%), 2 (22.2%) and 3 (75%), respectively, and daratumumab – 2 (16.7%), 2 (22.2%) and 4 (100%), respectively. The number of patients treated with daratumumab was significantly higher in group 3 compared to group 1; p=0.029. Summary/Conclusion: The data of the pilot study indicate a difference in the composition of lymphocytes in the apheresis product under different modes of mobilization. It is possible that the immune cell composition depends not only on the type of mobilization regimen, but also on the nature of the previous mobilization therapy, which needs to be confirmed with more data. Keywords: Multiple myeloma, Autologous hematopoietic stem cell transplantation, Autograft

Aim. To study the quality of life in patients with chronic immune thrombocytopenia (ITP) in the process of romiplostim therapy and to assess the efficacy and safety of this drug in real-world setting. Materials & Methods. The study enrolled adult patients with the confirmed chronic ITP diagnosis and indications for romiplostim therapy. Clinical parameters, RAND SF-36 and FACT-Th6 quality of life as well as FACIT-Fatigue scores were evaluated prior to romiplostim administration vs. 3, 6, and 12 months after the treatment onset. Patient satisfaction checklist was also administered at all study points after the start of therapy. The clinical efficacy of romiplostim was analyzed along with assessing response and time to response. To study the quality of life and fatigue changes, the Generalized Estimating Equation (GEE) method was used during the observation period. Significant fatigue changes were determined and compared in terms of the perception differences from patient’s and physician’s perspective. Results. The study enrolled 60 chronic ITP patients treated with romiplostim in the real-world setting (mean age 51.9 years, 70 % women). The median thrombocyte count prior to romiplostim therapy was 18.5 × 109/L (interquartile range 10.8–22.3 × 109/л). On the enrollment date, 90 % of patients showed hemorrhagic syndrome. Overall response to romiplostim therapy was 98.3 % (complete response was achieved in 93.3 % of patients). After 6 months of therapy, 89.5 % of patients preserved response. After 3 months of therapy, hemorrhagic syndrome was eliminated in 81 % of patients, after 6 months the same was achieved in 93 % of patients. The median time to response was 4.4 weeks (95% confidence interval 3.6–5.3 weeks). Adverse events of grades 1/2 associated with romiplostim were reported in 6.7 % of patients. On romiplostim therapy, pronounced positive changes in quality of life were shown by all scales of the general questionnaire SF-36 and the targeted questionnaire FACT-Th6 (p < 0.001). The clearest improvements were observed in role-physical and role-emotional functioning. Already after 3 months of therapy, a considerable fatigue reduction was observed and sustained for the next 6 and 12 months of romiplostim administration (p < 0.001). During the therapy, the proportion of patients with fatigue impacting various aspects of functioning became considerably smaller. The vast majority of patients (85 %) were satisfied with the treatment. Discrepancies between patients’ and physicians’ evaluations of fatigue were also identified during the treatment. Conclusion. The results of the present multi-center observational study demonstrate high efficacy and safety of romiplostim for chronic ITP patients in the real-world setting. Romiplostim therapy yields considerable quality of life improvement and fatigue reduction. To optimize the patient monitoring system and patient-centered ITP treatment in the real-world setting, it is advisable to use the standardized questionnaires assessing quality of life and fatigue.

Background. The novel coronavirus infection SARS-CoV-2 (COVID-19) is one of high-threat respiratory diseases, characterized by multiple organ disorders with primary respiratory failure and population mortality of 2–5 %. However, the mortality of oncohematological patients treated with chemotherapy is considerably higher. Aim. To analyze the COVID-19 treatment outcomes in hematological malignancy patients who received drug chemotherapy. Materials & Methods. The clinical course of COVID-19 was analyzed in 32 hematological malignancy patients aged 31–81 years (median 62 years). The disease onset was the date of the first positive COVID-19 PCR test. These patients were transferred to an infectious hospital specialized in the therapy of the novel coronavirus infection. Pneumonia was confirmed by standard radiography and CT. Blood oxygen saturation, body temperature, ECG, and respiratory rate were monitored. Moderate and severe COVID-19 was observed in 17 (53.1 %) of 32 patients. The condition of 15 (46.9 %) patients was described as good. For comparison, a control group was collected from 32- to 79-year-old (median 63 years) patients (n = 28) having hematological malignancies but no COVID-19. Results. Nine (28.1 %) of 32 patients under analysis died upon increasing respiratory and multiple organ insufficiency on Day 3–17 (mean 8,6 ± 4,6 days) from the first positive COVID-19 PCR test. Death was predominantly reported in multiple myeloma patients (n = 5) as well as in a patient with Waldenstrom’s macroglobulinemia. In the control group (n = 28) with similar hematological tumors but without COVID-19, three (10.7 %) patients died throughout the 12-month follow-up period. The present paper contains a case report illustrating the clinical features of coronavirus infection in a patient with Waldenstrom’s macroglobulinemia, a monoclonal gammopathy with primary bone marrow lesions. Conclusion. COVID-19 is a life-threatening viral disease with high mortality in patients with hematological malignancies, especially those with plasma cell dyscrasias.

Aplastic anemia (AA) is a non-neoplastic hematological disease closely associated with bone marrow failure which is typical of paroxysmal nocturnal hemoglobinuria (PNH) and myelodysplastic syndrome (MDS). The PNH clones can be detected in more than a half of AA patients at onset of the disease, and there is a probability for AA/PNH co-variants to progress to classic hemolytic PNH. At the same time, the AA patients treated by immunosuppressive therapy undergo the risk of disease transformation to MDS and acute myeloid leukemia. Currently known risk factors and possible precursors of such transformation are considered in the brief literature review. In addition to that, the paper provides a case report of AA/PNH transformation to MDS during complete AA remission after immunosuppressive therapy combined with a successful haploidentical transplantation of hematopoietic stem cells.

Background: It has been increasingly recognized that cancer progression is not an autonomous process driven and performed exclusively by cancer cells. Hematopoietic cells live in a complex mesenchymal environment ant this environment influences the cancer progression and vice versa is influenced by cancer cells. The tumor-educated microenvironment plays a role in immunosuppression, angiogenesis, and drug resistance. Being in contact with cancer cells, mesenchymal stem/stromal cells acquire cancer-associated phenotype. It is not known whether the hematopoietic niche is restored in multiple myeloma (MM) patients’ bone marrow after treatment. Aims: The aim of the work was to study hematopoietic niche in MM patients with different treatment outcome. Methods: Healthy donors (HD, n=2) and patients (n= 24) with different MRD status after bortesomib based therapy were enrolled in the study. Histological examination was performed on their trephines, bioinformatics analysis of aspirate transcriptomes was performed to analyze non-coding tandemly repeated RNA profile and the level of transcription of genes of WNT family, the results of computational analysis was checked in vitro by qPCR and in situ by DNA-RNA FISH of mesenchymal stem cells (MSC) of patients’ bone marrow. The interaction of of MSC and cancer cells was mimicked in coculture experiment with or without bortezomib. Results: The histology of MM hematopoietic niche of patients with partial response (PoCR) and non-responders (NR) was different from normal - the level of vessels density and a-smooth muscle actin staining (a marker of MSC/fibroblasts with cancer-associated phenotype) were significantly higher than in HD niche. MSC from MM patients were more resistant to bortezomib treatment and more effective in supporting cancer cells viability during incubation with the drug as compare with HD MSC. Moreover, MM MSC have prominent cancer-associated phenotype and increased transcription of some tandemly repeated sequences. We have found that transcription of several WNT family genes was downregulated in NR and PoCR patients. Our results give an evidence that MM hematopoietic niche is not returned to normal after treatment especially in patients non-responding or partially responding to it. Some of the genes of WNT family are involved in ostegenesis and they are downregulated in treated MM patients. Summary/Conclusion: MSC from MM patients have a number of features in morphology, genes and non-coding DNA expression profiles persisted after treatment. The work was supported by by the Ministry of Science and Higher Education of the Russian Federation (project 15.BRC.21.0011, Agreement № 075-15-2021-1063)

Mesenchymal stromal cells (MSC) 'educated' by tumor cells are an essential component of the multiple myeloma (MM) tumor microenvironment (TME) involved in tumor progression. Transcription of tandemly repeated (TR) non-coding DNA is often activated in many tumors and is required for tumor progression and cancer cells genome reorganization. The aim of the work was to study functional properties including the TR DNA transcription profile of MSC from the hematopoietic niche of treated MM patients. Healthy donors (HD) and patients after bortezomib-based treatment (with partial or complete response, PoCR, and non-responders, NR) were enrolled in the study. Their trephine biopsies were examined histologically to evaluate the hematopoietic niche. MSC cultures obtained from the biopsies were used for evaluation of the proliferation rate, osteogenic differentiation, presence of tumor MSC markers, resistance to bortezomib, and pericentromeric TR DNA transcription level. The MSC 'education' by multiple myeloma cells was mimicked in co-culture experiments with or without bortezomib. The TR DNA transcription profile was accessed. The histological examination revealed the persistence of the tumor microenvironment (especially of the vasculature) in treated patients. In co-culture experiments, MSC of bortezomib-treated patients were more resistant to bortezomib and protected cancer MM cells of the RPMI8226 cell line more effectively than HD-MSC did. The MSC obtained from PoCR and NR samples differed in their functional properties (proliferation capacity, osteogenic potential, and cancer-associated fibroblasts markers). Transcriptome analysis revealed activation of the TR transcription in cells of non-hematopoietic origin from NR patients' bone marrow. The pericentromeric TR DNA of HS2/HS3 families was among the most upregulated in stromal MSC but not in cancer cells. The highest level of transcription was observed in NR-MSC. Transcription of HS2/HS3 was not detected in healthy donors MSC unless they were co-cultured with MM cancer cells and acquired cancer-associated phenotype. Treatment with TNFα downregulated HS2/HS3 transcription in MSC and upregulated in MM cells. Our results suggest that the hematopoietic niche retains the cancer-associated phenotype after treatment. Pericentromeric non-coding DNA transcription is associated with the MSC cancer-associated phenotype in patients with ineffective or partially effective multiple myeloma treatment.

Aim. To study the value of PD-L1 protein expression in the combined model of diffuse large B-cell lymphoma (DLBCL) after administration of R-CHOP induction immunochemo-therapy. Materials & Methods. A retrospective analysis was based on the data of 85 DLBCL patients. The median age was 59 years (Q-Q3: 29-83). Each patient received at least 2-6 courses of R-CHOP immunochemotherapy. The median follow-up period was 17 months. The optimal cut-off threshold for assessing the proportion of tumor cells expressing PD-L1 protein was determined by the CART (Classification and Regression Tree) method. Results. Patients were divided into three groups depending on IPI (International Prognostic Index) risk and immunohis-tochemical subtype (Hans algorithm) using CART. In group 1 with immunohistochemical GCB subtype and any IPI risk, except for the high one, low PD-L1 expression measured in terms of the DLBCL expressing tumor cell count, was identified in 21 (84 %) patients, 4 (16 %) patients showed overexpression. In case of low PD-L1 expression the 2-year progression-free survival (PFS) was 76 % (median not reached). In 4 patients with protein overexpression, the life duration after DLBCL diagnosed was 4, 16, 2, and 6 months, respectively. In group 2 with immunohistochemical non-GCB subtype and any IPI risk, except for the high one, 27 (67.5 %) patients showed low, and 13 (32.5 %) patients showed high PD-L1 expression. The analysis of the 2-year PFS resulted in no significant differences in groups with different relative counts of PD-L1 expressing tumor cells, i.e., 46 % and 49 %, respectively (p = 0.803). In case of low (< 24.5 % tumor cells) PD-L1 expression, the 2-year overall survival (OS) was better than in patients with overexpression (> 24.5 % tumor cells), i.e., 87 % vs. 52 %, respectively (p = 0.049). In group 3 with IPI high risk irrespective of immunohistochemical subtype, the proportion of PD-L1 expressing cells was higher than cut-off threshold (> 24.5 %) in 9 (45 %) patients, low protein expression was identified in 11 (55 %) patients. Deaths were reported in all patients of group 3 showing PD-L1 overexpression. In case of low protein expression the proportion of patients alive was 46 % (p = 0.002). None of the patients with high PD-L1 expression lived longer than 2 years. In those with low PD-L1 expression the 2-year OS was 66 % (p = 0.008). Conclusion. Overexpression of PD-L1 by DLBCL tumor cells together with high IPI progression risk and non-GCB tumor subtype is associated with the worst OS and PFS. It can probably be accounted for by insufficient efficacy of R-CHOP induction immunochemotherapy in patients with high IPI risk. With this presumption, the PD-L1 expressing tumor cell count can be regarded as an important additional criterion for stratification of DLBCL patients into risk groups. Adding this new parameter to already established ones would probably contribute to differentiated approach to the choice of chemotherapy strategy at the onset of this aggressive lymphoma.

Vitaly N. Chebotkevich, Alena V. Kuleshova, Anastasia A. Zhernyakova, Ivan I. Kostroma, Ekaterina E. Kiseleva, Elena I. Kaytandzhan, Natalia Yu. Semenova, Stanislav S. Bessmeltsev, Alexander V. Chechetkin, Sergei V. Gritsaev Russian Research Institute of Hematology and Transfusiology, St. Petersburg , Russia Infectious complications in multiple myeloma patients undergoing autologous peripheral blood stem cell transplantation Cellular Therapy and Transplantation (CTT). Vol. 10, No. 1, 2021 doi: 10.18620/ctt-1866-8836-2021-10-1-63-68 Submitted: 27 December 2020, accepted: 12 March 2021