Background. The application of convalescent plasma (CP) is currently seen as a feasible therapeutic approach in the treatment of COVID-19.

Aim. To analyze the experience of recruiting a donor cohort from COVID-19 convalescents for banking of CP as part of a pilot project at the Moscow Healthcare Department.

Materials and methods. A retrospective research included 493 COVID-19 convalescents as potential CP donors, all examined at the Sklifosovsky Research Institute for Emergency Medicine. CP was banked using the plasmapheresis method. Only those donors with a documented medical history of COVID-19, which was confi rmed by polymerase chain reaction of SARS-CoV-2 RNA in pharyngeal swabs, and no sooner than 14 days after complete recovery were eligible for donation. Viral neutralizing activity (VNA) was chosen as the key characteristic of the immunological viability of CP. All the donors having VNA titers were characterized in terms of gender, age, time interval since the disease onset, regression of clinical symptoms and clinical features of the COVID 19 course.

Results. Effective (1:160 or more) and acceptable (1:80) VNA titers were found in 21.1 % and 24.75 % of donors, respectively. Signifi cant predictors for a donor having a high VNA titer included: male sex, age over 36 years and verifi ed viral pneumonia. The absence of a signifi cant body temperature response (38.5 °С) can be considered as a negative marker of a potential donor.

Introduction. The bacterial contamination of blood components represents an on-going challenge in transfusion medicine although dramatic achievements have been achieved in reducing remaining risk of viral infections of blood donors and noninfectious complications of blood transfusion.

Aim: to evaluate trends of bacterial contamination of blood components and measures for its reduction in one blood collection center in recent years.

Materials and methods. The research material presented is comprised of the results of microbiological testing of blood components, collected at the Republican Center for Transfusiology & Medical BioTechnologies, during 2012–2018, as well as the data of aerosol particles 0.5 and 5.0 μm in air volume of 1 m3 and bacterial contamination of air on working areas. Both microbiological, visual, and statistical methods were used in the study.

Results. The data presents results of change in rate of blood components collection, samples taken for microbial analysis, and positive bacterial cultures in Belarusian Republican Center for Transfusiology & Medical Bio Technologies in 2012–2018. As shown, there was low rate of bacterial contamination of plasma and platelet components. The positive results of bacterial contamination of platelets were attributed to doses obtained from whole blood, but not by automatic apheresis. A trend in decrease in the rate of bacterial contamination frequency (р < 0,001) was observed for red cell components from 1,21 (95 % CI 0,39–3,28) in 2012 to 0 (95 % CI 0–0,8) in 2018 per each 100 doses, taken for microbial testing. This was associated with increasing the frequency of doses taken for microbial testing and carrying out the organizational measures in 2015–2016 to reduce airborne bacterial contamination in working areas of blood collection and separation.

Conclusion. The risks of bacterial contamination of erythrocyte — containing, but not other blood components in the organization of blood transfusions were reduced during 2012–2018 due to certifi cation of working areas according to cleaning room classifi cation and other organizational measures.

Introduction. The pathogenesis of myeloproliferative neoplasms is associated with the chimeric gene BCR-ABL1 or with one of the driver mutations in the genes JAK2, MPL and CALR (Calreticulin). However, the classifi cation of the World Health Organization lists no myeloid neoplasms with more than one driver genetic abnormality.

Aim. To search for mutations in the genes JAK2, MPL and CALR in patients with BCR-ABL1-positive chronic myeloid leukemia (CML), as well as to evaluate the kinetics of the discovered mutations during tyrosine kinase inhibitor (TKI) therapy.

Materials and methods. mRNA and DNA samples isolated from blood and bone marrow cells of 567 CML patients, who underwent periodic monitoring of the BCR-ABL1 transcript level over the 2012–2019 period were included in the study The BCR-ABL1 transcript level was determined using a highly sensitive quantitative real-time polymerase chain reaction. The mutations JAK2V617F and MPLW515L/K were detected using real-time quantitative allele-specifi c polymerase chain reaction. Mutations in the CALR gene were investigated using fragment analysis followed by Sanger sequencing.

Results. The combination of the BCR-ABL1, JAK2 and CALR gene mutations among CML patients receiving TKIs was 1.23 % (7/567). Out of these, the combination of BCR-ABL1 with JAK2V617F and the combination of BCR-ABL1 with CALR gene mutations were detected in 0.88 % (5/567) and 0.35 % (2/567) of cases, respectively. During TKI therapy, in 5 out of 7 patients, the level of BCR-ABL1 reached major molecular response (MR). In 4 of these patients, the therapy was discontinued. These patients are currently in molecular remission. In the remaining 2 patients, major MR was not achieved, despite the use of second-generation TKI preparations.

Conclusions. The combination of the BCR-ABL1 chimeric gene with gene mutations Jak2 or CALR was a rare event and amounted to 0.88 and 0.35 % of cases, respectively. The combination of BCR-ABL1 with Jak2V617F and CALR mutations does not always impede the achievement of major MR.

Introduction. Biofi lm-forming ability among Candida spp. on indwelling medical devices may have a negative infl uence on the outcome of invasive candidiasis in various groups of patients.

Aim. The objective of this study was to evaluate the biofi lm-forming ability among Candida spp. isolated from clinical specimens in patients with hematological malignancies and patients without hematological malignancies.

Materials and methods. Biofi lm production among Candida spp. was studied using XTT (Sigma-Aldrich, USA) reduction assay. Candida spp. were classifi ed as biofi lm-forming, having optical density equal to and more than 0.1, and non-biofi lmforming with optical density less than 0.1.

Results. A total of 428 Candida spp. (C. albicans n = 192, C. parapsilosis n = 121, C. krusei n = 40, C. tropicalis n = 38, C. glabrata n = 37) were evaluated (172 from hematological patients, 256 from non-hematological patients, 361 from blood culture, 67 from other sterile specimens). Biofi lm-forming ability was detected among 179 (41.8%) Candida spp. with the same rate in hematological patients and non-hematological patients (41.9 % and 41.8 %, respectively). Biofi lm production predominated among non-C. albicans (52.5 %) compared to C. albicans (28.6 %, p = 0.001). Biofi lm production prevailed among C. tropicalis (89.5 %) and C. krusei (75 %) compared to C. parapsilosis (41.3 %), C. albicans (28.6 %), and C. glabrata (27 %, respectively, p < 0.05). Biofi lm-forming ability among C. tropicalis and C. krusei dominated in both groups of patients. Biofi lm production among C. albicans prevailed in non-hematological patients compared to hematological patients (34.1% vs 18.2%, p = 0.03). There were no differences in biofi lm production among Candida spp. isolated from blood culture (42.9%) and other sterile specimens (35.8%, p = 0.3).

Conclusion. Biofi lm-forming ability varied among the Candida spp. and prevailed among C. tropicalis and C. krusei. Biofi lm production among Candida spp. was detected with the same rate in hematological and non-hematological patients.

Introduction. One of the problems in providing Russian transplant clinics with unrelated hematopoietic steam cells (HSCs) is the lack of an interaction scheme “Registry — HSC collection center — Transplant center”. In order to ensure effective operation at the donor activation stage, registries need regulated and stable cooperation with the Collection center with a clear distribution of duties and responsibilities for both parties.

Aim: to evaluate the effectiveness of the Kirov Registry.

Materials and methods. Since 2009, the Kirov Registry has been systematically working with HSC donors (as of 25/11/2019, the total number of donors was 46,922, of which 43 % male, 57 % female; 49 % regular blood donors, 51 % volunteers from donor actions) since 2013. The Registry has its own Collection Center. The effectiveness of the Registry was evaluated by indicators: the number of donations, donor activation time, the number of refusals at the stages of preliminary activation and donation of cellular material.

Results. As of 25/11/2019, more than 1,000 preliminary activations of potential HSC donors were performed, of which 175 were completed by collection of HSCs. The use of the created and validated activation model with the employment of the Registry and the Collection Center currently provides the following activation times: the period for sending a sample for confi rming HLA typing does not exceed 14 days; the total time to satisfy the transplant center request for cellular material does not exceed 2 months. A detailed analysis of the causes of refusals at the stages of preliminary activation and after receiving a request for the collection of cell material was carried out.

Conclusion. Between 2009 and 2019 the Kirov registry has developed a model of effective work with the donors of the HSCs at all stages of the chain “Registry — HSC collection center — Transplant center”. The effectiveness of the work is confi rmed by the demand for donors, observance of the donor activation time, and a relatively low percentage of refusals from donations.

Introduction. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a standard treatment for many patients with hematological malignancies. Over the past 20 years, an increase in transplantation activity has been noted throughout the world. About 50 % of all allo-HSCT are transplanted from unrelated donors.

Aim: to present the dynamics and stages of the development of unrelated donation using the example of one transplant center.

Materials and methods. This study analyzed Allo-HSCT performed from 2009 to March 2019 at the National Research Center for Hematology (NRCH). The work of the unrelated donor recruiting group and the tissue typing laboratory was analyzed for this period. 107 patient requests for unrelated donor search were dissected to identify search failures. The parameters of 206 unrelated donors were estimated depending on the register (Russian Federation/foreign).

Results. The number of allo-HSCTs did not exceed more than 20 per year, in 2009–2011. Since 2012, the number of alloHSCT significantly increased when the possibility for searching for unrelated donors abroad as well as in the Russian Federation (RF) databases appeared. During this time an increase by more than 50 % was noted in the number of allo-HSCTs. Allo-HSCs from unrelated donors of the Russian Federation make up 30–40 % of all unrelated allo-HSCs. 16 % of potential donors of hematopoietic stem cells included in the NRCH registry are donors of the human blood components. Despite the increasing number of unrelated donors in international and RF databases, 12 % of patients did not find a compatible donor in any of the registers, due to a rare combination of HLA genes. It was revealed that among donors from the RF from whom alloHSCT was performed, there was not a significant prevalence of men, compared to the foreign registry, 50.7 % and 66.7 %, respectively, despite the preference of donor-male by doctors. The 5-year overall survival in patients with acute leukemia in the first complete remission, depending on the performance of allo-HSCT from a donor from the RF or foreign registers, are comparable, 40 % and 39.5 %, respectively.

Conclusion. The number of allo-HSCT has increased 5 times over the past 10 years largely due to the development of unrelated donation: 30–40 % of allo-HSC transplants received from unrelated donors were performed from donors from the United database of the Russian Federation. The 5-year overall survival of these patients is comparable with the results of the overall survival patients who received transplants from donors from foreign registers.

Introduction. An unfavorable prognosis in chronic lymphocytic leukemia (CLL) is associated with unmutated status of rearranged IGHV genes. CLL is also characterized by a narrowing of the repertoire of IGHV genes and the formation of quasiidentical (stereotyped) receptors, which is probably associated with antigenic selection of the tumor B-cell clone in the pathogenesis of the disease. The HLA phenotype plays an important role in antigenic selection of B cells. On the other hand, the association of specifi c HLA alleles with various diseases has been described.

Aim. To assess the frequencies of HLA alleles in CLL patients with unmutated IGHV genes and the most common stereotyped receptors (SARs).

Materials and methods. The study included 100 CLL patients with unmutated IGHV genes - 50 with the most common stereotyped antigen receptors (SARs) and 50 with non-stereotyped antigenic receptors. Control group of healthy donors was also included.

Results. Signifi cant differences in HLA-allele repertoire between this two groups of patients and groups of donors were found. B*18 allele group was found much more common in patients with SARs than in donors and in patients without SARs. HLA-B*39 was more frequent for patients with SARs compared to donors; in patients without SARs these alleles were not found. For all patients, the frequency of HLA-B*52 alleles was higher than for donors. HLA-C*12 allelic group was found more frequent in CLL patients than in donors. HLA-DRB1*15 in CLL patients with SARs was found twice as often as in healthy donors or patients without SARs, while HLA-DRB1*13, oppositely, was found twice as rare. HLA-DRB1*16 was signifi cantly more frequent in patients without SARs, compared with donors and the patients with SARs. No signifi cant differences were found in the HLA-A and HLA-DQB1 loci.

Conclusion. The association of two HLA alleles with “unmutated” CLL and two others with CLL bearing prognostically unfavorable SARs was found. HLA typing of expanded samples of CLL patients with different prognosis and course of the disease will provide more information on the mechanisms of antigen selection in the pathogenesis of CLL and improve diagnostic and therapeutic approaches.

Introduction. Human immunodeficiency virus (HIV), Hepatitis B and C viruses (HBV, HCV) are the major blood-borne infections. Donor blood components cannot be currently replaced with synthetic substitutes, which determines the necessity of improving the viral safety of blood component transfusions.

Aim. To describe a multicomponent system for monitoring the viral safety of donor blood component transfusions.

General findings. Measures ensuring the safety of blood component transfusions include the maintenance of regular communication with donors, pre-donation laboratory tests, viral screening, production, storage and clinical use of blood products, as well as monitoring of blood transfusion results. The selection of donors from low-risk behaviour groups ensures the viral safety of blood transfusion procedures at the initial stages of blood production. A necessary condition for improving the safety of transfusions is additional examination of donor blood samples for antibodies against the hepatitis B core antigen. Algorithms are described for investigating the initial occurrence of infectious markers in blood transfusion recipients, a retrospective investigation in cases where viral infection markers are identified in recurrent donors, as well as for the monitoring of the virological status of patients with blood system disorders. The implementation of these measures can increase the overall safety of blood transfusion.

Introduction. Interleukin-3 (IL-3) is the key cytokine involved in the regulation of normal haematopoiesis. Some leukemic cells demonstrate high expression of the α-subunit of the receptor for interleukin-3 (CD123).

Aim: to summarize the current understanding of IL-3 and its receptor CD123 in the pathogenesis of acute leukemia.

General findings: IL-3 regulates the proliferation and differentiation of normal hematopoietic progenitor cells in the early stages of hematopoiesis. The IL-3 receptor (CD123) is expressed on normal hematopoietic cells. High expression of CD123 was confirmed on blast cells of AML, B-ALL and on the leukemia-initiating CD34+ CD38– cells. IL-3 inhibits apoptosis and promotes the autonomous growth of blast cells. Currently, different approaches of blocking the IL-3 mediated signal are being investigated.

Introduction. Cryosupernatant is blood component. Cryosupernatant is the supernatant plasma removed during the preparation of cryoprecipitate.

Aim. To provide information on the composition and methods of production, storage, transportation and clinical use of Cryosupernatant.

General findings. In comparison with fresh frozen plasma (FFP) and cryoprecipitate, Cryosupernatant plasma is depleted in factor VIII, fibrinogen factor von Willebrand (VWF). Cryosupernatant is deficient in high molecular weight multimers of VWF, but contains VWF metalloproteinase. The concentrations of factor V, antithrombin III, albumin and immunoglobulins are the same as in FFP and cryoprecipitate. The indications for Cryosupernatant transfusions are massive blood loss in patients with factor VIII inhibitor, plasma exchange in patients with thrombotic thrombocytopenic purpura. For children the doses of Cryosupernatant should be 10-15 mL/kg.