Introduction. Non-chemotherapy for acute promyelocytic leukaemia (APL) with a combination of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) provides for a high patient survival rate at lesser toxicity as effectively or superior to standard chemotherapy programmes.

Aim — assessment of the ATO–ATRA risk-adapted exposure protocol in management of de novo acute promyelocytic leucaemia.

Materials and methods. A prospective study included 51 primary APL patients aged 18–76 years. The program included remission induction (ATO 0.15 mg/kg intravenously, ATRA 45 mg/m2 orally) for 30–60 days in a low-risk (until remission) and 60 days — in a high-risk cohort that had idarubicin therapy added on days 2 and 4. Remission consolidation was attained with four (low-risk) or five (high-risk) courses. Minimal residual disease was monitored with real-time PCR at all phases.

Results. The high-risk cohort was assigned 15 (29.4 %), the low-risk cohort — 36 (70.6 %) patients. Therapy induction till APL morphological remission was performed in 48/51 (94 %) patients. Molecular APL remission was achieved in 47 (92 %) patients, 100 % in the low-risk and 80 % in high-risk cohort. Early mortality was 6 % (n = 3), death in remission — 2 % (n = 1). Differentiation syndrome (DS) occurred in 16 (31.7 %) patients, more frequently in the high-risk vs. low-risk cohort (53.3 % and 22.2 %, respectively, p = 0.05; odds ratio 4.0 [1.1–14.4]). DS developed on days 1–20 (3 days median) of therapy. DS risk factors: a high-risk status, haemorrhagic syndrome and infection at the disease onset. A median follow-up time in survivors was 12.9 months (2.5–34.3), a six-month overall survival — 92 % (95 % CI: 85–100 %). A six-month overall survival was 100 and 73 % in the low- and high-risk cohorts, respectively (95 % CI: 54–100 %, p = 0.001). APL relapse not registered, 47 (92 %) patients survived and achieved the first molecular remission.

Conclusion. A differentiated risk-adapted approach to APL therapy with cytostatic treatment added in high-risk patients only provided for a 100 % molecular remission and relapse-free survival. Therapy failures (early mortality and death in remission) affected high-risk patients due to a severe individual condition at the time of APL diagnosis.

Introduction. The Russian multicentre trial on treatment of Acute Lymphoblastic Leukaemia (ALL) in adults (RALL-2016) regulates a centralised detection of minimal residual disease (MRD) on days 70 (end of induction II), 133 (end of consolidation III) and 190 (end of consolidation V).

Aim — the assessment of tumour cell clearance and normal B-cell precursor, mature B-cell and plasma cell dynamics.

Materials and methods. The study period of December 2016 — August 2019 covered 59 B-ALL patients; the control cohort included four allogeneic blood stem cell donors. The MRD detection was performed with bone marrow samples in flow cytometry.

Results. The patient majority have reached MRD-negativity at control timepoints, 60.4, 75.6 and 91.2% on days 70, 133 and 190, respectively. No correlation was observed between MRD values and tumour cell immunophenotype. B-cell precursors were undetected in 54.4, 38.8 and 59.4% patients on days 70, 133 and 190, respectively. Mature B-cells were fewer compared to donors’ on days 133 and 190. The relative plasma cell count did not differ significantly over therapy and between patients and donors.

Conclusion. The RALL-2016 protocol facilitates MRD-negativity in the patient majority despite reduced cytostatic intensity.

Introduction. The patient survival after allogeneic haematopoietic stem cell transplantation (allo-HSCT) from an unrelated or related haploidentical donor is improved in a donor–recipient match resolution at the level of non-coding region identity of HLA genes. Next-generation sequencing (NGS) allows detection of point substitutions in HLA non-coding regions.

Aim — assessment of the NGS-based HLA-typing performance.

Materials and methods. An NGS-based HLA-typing of 1,056 DNA samples from allo-HSCT recipients, their related and registry donors was performed with AllTypekit chemistry (OneLambda, USA). A parallel HLA-typing assay of 96 samples by 8 genes (A/B/C/DRB1/DRB3/DRB4/DRB5/DQB1) was accomplished within one working week.

Results. HLA class I genes were typed at a 4-field (allelic), and HLA class II genes — 2–4-field (high to allelic) resolution. An allelic-resolution typing of HLA class I genes in a Russian population (657 registry donors) was conducted for the first time. The most frequent HLA alleles have been identified: А*02:01:01:01 in HLA-A (26.9 %), B*07:02:01:01 in HLA-B (12.5 %) and C*07:02:01:03 in HLA-C (12.6 %). The most frequent HLA class II variants were DRB1*07:01:01 (14.1 %), DRB3*02:01:01 (18.0 %), DRB4*01:03:01 (18.9  %), DRB5*01:01:01 (13.5  %), DQB1*03:01P (17.4  %).

Conclusion. An NGS-geared HLA-typing has yielded low-ambiguity allelic and high-level resolution results in a parallel sequencing assay with a large number of samples. The method implemented detects genetic polymorphisms also in non-exonic non-coding regions of HLA genes and facilitates typing in candidate HSCT recipients, related and unrelated donors.

Introduction. Multiple myeloma (MM) is a B-cell malignancy with clonal expansion of plasma cells in bone marrow. Highdose chemotherapy with autologous haematopoietic stem cell transplantation is among main consolidation therapies in MM. Myeloid-derived suppressor cells (MDSCs) are immature myeloid-accompanying cells able to suppress the immune response. The administration of granulocyte colony stimulating factor (G-CSF) to mobilise haematopoietic stem cells (HSCs) increases the MDSC count in peripheral blood (PB).

Aim — to study MDSC subsets in PB of remission MM patients and their incidence dynamics at HSC mobilisation.

Methods. The study surveyed 35 MM patients prior to and after HSC mobilisation. The counts of granulocytic (G-MDSCs; Lin–HLA-DR–CD33+ CD66b+), monocytic (М-MDSCs; CD14+ HLA-DRlow/–) and early MDSCs (E-MDSCs; Lin–HLA-DR– CD33+ CD66b–) were estimated in flow cytometry.

Results. Remission MM patients differed from healthy donors in higher relative counts of G-MDSCs (Lin–HLA-DR– CD33+ CD66b+) and increased relative and absolute counts of М-MDSCs (CD14+ HLA-DRlow/–). М-MDSCs significantly outnumbered G-MDSCs. MDSC subset counts were elevated in complete response (CR) and very good partial response (VGPR), as well as in partial response (PR). Higher relative MDSC counts were associated with greater pretreatment (2–3 lines of chemotherapy). After HSC mobilisation with cyclophosphamide 2–4 g/m2 + G-CSF (filgrastim 5 μg/kg/day), the median relative E-MDSC and M-MDSC counts increased by 2.3 and 2.0 times, respectively, while the relative G-MDSC count raised 46-fold perturbing the MDSC subset balance.

Conclusion. Remission MM patients had the increased relative G-MDSC and both relative and absolute M-MDSC counts compared to donors. A greater patient pretreatment was associated with higher relative G-MDSC counts. Treatment response (CR/VGPR vs. PR) was not coupled with MDSC count variation. The G-CSF-induced HSC mobilisation entailed a significant expansion of all three MDSC subsets in PB.

Introduction. A prothrombin-mutant genotype is a known risk factor in gestational complications.

Aim — efficacy assessment in pregravid heparin prevention of pre-eclampsia (PE) and foetal growth retardation (FGR) in females with F2G20210A genotype and suprathreshold prothrombin activity.

Patients and methods. A single-centre randomised controlled study enrolled 80 pregnant women carrying prothrombin F2G20210A. The inclusion criterion was a pregravid plasma prothrombin activity > 171 %. The study cohort consisted of 50 women (mean age 31.2 ± 3.7 years) receiving low molecular-weight heparin (LMWH) in menstrual cycle at weight-based elevated prevention doses. A comparison group comprised 30 pregnant women (mean age 31.3 ± 2.9 years) not receiving LMWH prophylaxis.

Results. A pregravid start of LMWH treatment at high prophylactic doses in F2G20210A genotype carriers with prothrombin activity > 171 % allowed an absolute risk reduction (ARR) of PE by 46.7 % [p = 0.0001; number needed to treat (NNT): 2.1; 95 % confidence interval (CI) 3.4–1.56], severe PE by 30.7 % [p = 0.0001; NTT: 3.3; 95  % CI (6.7–2.2)] and FGR by 30.7 % [p = 0.0001; NTT: 3.3; 95 % CI (6.7–2.2)].

Conclusion. Use of LMWH is justified in prevention of placenta-mediated complications in F2G20210A genotype carriers with a suprathreshold-high prothrombin activity.

Introduction. Occult hepatitis B virus (HBV) revelation in HBV nuclear antigen testing is of particular importance to prevent transfusion infection.

Aim — the identification of factors affecting the anti-HBc detection rate in donated transfusable blood components from different regions of Russia.

Materials and methods. A cohort screening single-stage epidemiological study was conducted with 2,000 donor blood samples, 500 samples per each of four regions of the country, the Republics of Crimea (Simferopol) and Sakha (Yakutia), the cities of Saransk and Orenburg. Data on 968 blood samples from the National Research Center for Hematology’s donor bank were used as reference. The testing targeted HBV nuclear antigen antibodies. Positive donated blood samples were additionally tested for IgM and virus surface antigen antibodies using Abbott and Vector-Best commercial reagent kits.

Results. Donor demographic profiles differed insignificantly across members of the Russian Federation. Males predominated among the donors (69.6 %). Anti-HBc was detected in 219 of 2,000 samples examined (10.9 %). The donor blood sample anti-HBc detection rate ranged from 6.0 to 21.6 %, depending on the region. Anti-HBc-positive proportions in Orenburg, Crimea, Mordovia and Sakha comprised 8.2, 8.0, 6.0 and 21.6 %, respectively (p < 0.01). First-time donors had anti-HBc in 8.06, regular donors — in 11.29 % cases. The anti-HBc detection rate varied with donor’s age, being zero or near 1 % in 20-yo or younger people. Acute HBV antibodies had zero rate in Orenburg at zero or low-titre (< 100 mIU/mL) protective antibodies; 31 total samples, 15 low-titre and 16 negative for protective antibodies. In Simferopol, acute phase antibodies were negative in 7 blood samples containing high-titre protective antibodies (> 100 mIU/mL) and in 5.0 % samples with their low or zero levels. In Yakutian donors, acute phase antibodies were revealed only at protective antibodies negative. In Saransk, this marker was equal-proportion at zero and high-titre protective antibodies (3.3 % each).

Conclusion. Transfusion component procurement from younger donors should be prioritised as enhancing haemotransfusion viral safety. Positive occult HBV tests were less common in regions with low HBV incidence.

Introduction. Among main curative substances in acute lymphoblastic leukaemia/lymphoma (ALL/LBL) is 6-mercaptopurine (6-MP). However, the severity of adverse reactions (ADRs) to this drug varies considerably among patients, which is sometimes conditioned by individual single nucleotide polymorphisms in key 6-MP metabolism enzyme genes.

Aim — a literature review on the role of TPMT and NUDT15 gene variants in 6-MP metabolism in ALL/LBL.

Main findings. The TPMT and NUDT15 genes encode enzymes mediating key steps of the 6-MP metabolism. The metabolites determine the 6-MP therapeutic and toxic properties, with ADRs emerging when their concentrations alter. A number of TPMT and NUDT15 single nucleotide polymorphisms are associated with varied activities of the encoded enzymes, and their allelic combinations condition functional and non-functional phenotypes. Non-functional variant carriers more likely develop toxicity on 6-MP treatment compared to functional phenotypes. Non-functional TPMT/NUDT15 carriers should have the 6-MP dosage reduced to minimise emerging ADRs.

Introduction. Current knowledge of tumour biology attests a dual genetic and epigenetic nature of cancer cell abnormalities. Tumour epigenetics research provided insights into the key pathways mediating oncogenesis and facilitated novel epigenetic therapies.

Aim — an overview of intricate involvement of epigenetic change in haematological morbidity and current therapeutic approaches to target the related mechanisms.

Main findings. We review the best known epigenetic marks in tumour cells, e.g. DNA cytosine methylation, methylation and acetylation of histone proteins, the underlying enzymatic machinery and its role in oncogenesis. The epigenetic profile-changing drugs are described, including DNA hypomethylating agents, histone deacetylase and methylase inhibitors. A particular focus is made on substances currently approved in haematological therapy or undergoing clinical trial phases for future clinical availability.

Introduction. Recommendations cover the current state of diagnosis and treatment of mastocytosis.

Aim — а consolidation of the Russian experts’ opinion on treatment for adult mastocytosis.

Main findings. The recommendations have been developed taking into account foreign literature, national experience and world clinical evidence on therapy for systemic and cutaneous mastocytoses, mast cell leukaemia and other mastocytosis forms. The significance of bone marrow and peripheral blood molecular genetic testing for the presence of KITD816V gene variants is demonstrated. The treatment regimens described are based on midostaurin, imatinib, cladribine, hydroxycarbamide, interferon alfa and haematopoietic stem cell transplantation. Prognosis in different forms of mastocytosis is provided.