Anti-SARS-CoV-2 vaccination leads to the production of neutralizing as well as non-neutralizing antibodies. In the current study, we investigated the temporal dynamics of both sides of immunity after vaccination with two doses of Sputnik V against SARS-CoV-2 variants Wuhan-Hu-1 SARS-CoV-2 G614-variant (D614G), B.1.617.2 (Delta), and BA.1 (Omicron). First, we constructed a SARS-CoV-2 pseudovirus assay to assess the neutralization activity of vaccine sera. We show that serum neutralization activity against BA.1 compared to D614G is decreased by 8.16-, 11.05-, and 11.16- fold in 1, 4, and 6 months after vaccination, respectively. Moreover, previous vaccination did not increase serum neutralization activity against BA.1 in recovered patients. Next, we used the ADMP assay to evaluate the Fc-mediated function of vaccine-induced serum antibodies. Our results show that the antibody-dependent phagocytosis triggered by S-proteins of the D614G, B.1.617.2 and BA.1 variants did not differ significantly in vaccinated individuals. Moreover, the ADMP efficacy was retained over up to 6 months in vaccine sera. Our results demonstrate differences in the temporal dynamics of neutralizing and non-neutralizing antibody functions after vaccination with Sputnik V.

Wiskott–Aldrich syndrome (WAS) is a rare X-linked primary immunodeficiency characterized by microplatelet thrombocytopenia, eczema, frequent infections and an increased risk of autoimmune disorders and malignant neoplasms. Mutation detection in WAS gene is the gold standard for diagnosis of this disorder. This gene encodes a WASP protein, which works as regulator of cell cytoskeleton and is involved in the transmission of many intracellular signals. Nowadays there is no rapid and reliable method that allows to confirm WAS in a short period of time. Early detection of WAS in patients enables initiation of a donor search and preparation for the HSCT procedure. It also helps to avoid the development of severe and life-threatening conditions during waiting for genetic confirmation of the diagnosis by using pathogenetic therapy. Currently flow cytometry is one of the leading laboratory methods that permits to get the information about the expression of a protein in several hours. The study below describes rapid and reliable based on flow cytometry assay for WAS diagnosis. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology. The study included 46 patients with suspected WAS from 2 months to 17 years old. Patients were examined from January 2018 to January 2020. WAS gene defect was confirmed in 35 patients. It was calculated that normal threshold value for WASP expression is 7.07 with sensitivity and specificity 100% and 93.1% respectively. Besides negative correlation between WASP expression index and WAS clinical severity was shown (r = –0.63). This flow cytometry assay can be used for chimerism detection in WAS patients after HSCT. The flow cytometry assay for WASP protein evaluation is rapid, highly sensitive and highly specific. It allows to speed up diagnosis of this disorder.

Х-linked lymphoproliferative syndrome (XLP) is a life-threatening primary immunodeficiency, characterized by hemophagocytic lymphohistiocytosis, lymphoproliferation and hypogammaglobulinemia. The most frequent forms of XLP – XLP1 and XLP2 – are caused by mutations of the SH2D1A and BIRС4/XIAP genes, coding for SAP and XIAP proteins, respectively. Early diagnosis is important as it allows to prevent severe complications by introducing specific therapy and proceed to hematopoietic stem cell transplantation. Here we describe validation of precise and fast flow cytometry-based method of XLP1 and XLP2 laboratory diagnostics. This study is supported by the Independent Ethics Committee and approved by the Academic Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology. 89 patients from 2 months to 18 years of age seen at our Center from July 2016 to February 2020 with symptoms suspicious of XLP were included in the study. Decrease of SAP intracellular expression was found in 9 patients, and XIAP – in 10 patients. In all of them XLP diagnosis was confirmed by detection of SH2D1A or XIAP mutations, respectively. Female mutations carries from the families of these patients demonstrated abnormal expression of respective proteins. Analysis of the data allowed to calculated the optimized cut-off numbers for the SAP and XIAP expression, which was 50% and 80% in T lymphocytes (respectively) and 45% и 75% in NK lymphocytes (respectively). Specificity and sensitivity of the method was 100% for both proteins. Therefore the method of assessment of SAP and XIAP intracellular expression via flow cytometry allows fast and precise diagnostics of XLP1 and XLP2.

Compensatory or revertant somatic mutations (RSM) is a well-known phenomenon in patients with PIs. RSM can lead to the restoration of functional protein expression in some cell populations and thus influence the severity of clinical manifestations in patients with PI. The WAS gene, a mutation that leads to the development of Wiskott–Aldrich syndrome (WAS), is associated with high levels of RSM. In our study, we aimed to describe in detail the RSM phenomenon in patients with WAS, and also to try to study its effect on the severity of the clinical phenotype. Materials and methods of research: a single-center, prospective, open, continuous, non-randomized, comparative study was conducted. The study included 39 male patients with WAS from 2 months and up to 18 years old with mutation in WAS gene, who underwent assessment of WASP expression using flow cytometry. In 2 out of 9 patients, use of magnetic selection made it possible to isolate a population of lymphocytes expressing WASP. Germinal and somatic mutations were identified using Sanger sequencing. To assess severity of clinical manifestations of WAS, the original detailed scoring classification was used. Results: 9 patients had bimodal expression of WASP, which equaled to 23% of all examined. The median age of these patients was 3 years [7 months. – 15 years]. In two patients a presence of RSM was confirmed in WASP-expressing populations. Linear assessment of partially restored WASP expression revealed different patterns of lymphocyte subpopulation involvement in all 9 patients. The effect of RSM on the severity of clinical manifestations of WAS in the studied group of patients was statistically insignificant (p=0,39). Conclusion: according to the data obtained, patients with WAS, demonstrating a bimodal pattern of WASP expression, represent a very heterogeneous group in terms of the severity of clinical manifestations, involvement of cell populations, and the nature of RSM. This work is a methodological prerequisite for further comprehensive study of RSM phenomenon in patients with various PIs.

Динамика и функциональная характеристика антител и В-клеток памяти к SARS-CoV-2 в периферической крови у перенесших COVID-19 пациентов за период до