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Heart transplant patients are at an increased risk of COVID-19 infection adverse outcomes because of underlying immunosuppression and concomitant comorbidities. To date, all large-scale randomized controlled trials for various COVID-19 vaccines have excluded solid organ transplant recipients. Therefore, the efficacy and safety of coronavirus infection prevention using COVID-19 vaccines in transplant heart patients has not been sufficiently studied. In this research, the evaluation of virus-specific immunological reactions after vaccination (double Vero Cell vaccination and Sputnik Light booster vaccination) in heart transplant patients has been carried out. In vaccinated heart transplant individuals who did not have a history of COVID-19, starting from 4–6 months after the 2nd dose of the vaccine, an increase in antibodies to S protein level of was observed, while maintaining statistically significant differences for 9–12 months after vaccination (regardless of whether with or without booster vaccination). However, the concentration of antibodies remained low, and 37% of patients detected no antibodies. In vaccinated heart transplant individuals following the previous COVID-19 infection, as compared to seronegative patients, post-vaccination immunity is accompanied by maintaining a high level of virus-specific IgG antibodies to the S protein of the SARS-CoV-2 virus in the dynamics of the post-vaccination period with a statistically significant increase of these antibodies by 9–12 months after booster vaccination. The specific cellular response (according to the assessment of CD3⁺154⁺ and CD3⁺IFNγ⁺ TNFα⁺ cells) to the S protein of the SARS-CoV-2 virus remained low throughout the entire follow-up period, was recorded in 5–40% of heart transplant patients and statistically significant changes in the number of spikereactive lymphocytes were observed in patients with a history of COVID-19 by 4–6 months after administration of the 2nd dose of the vaccine. This, together with the results of the assessment of the humoral response, indicates a more pronounced post-vaccination immunity in patients with a hybrid immunity. While developing a methodology for assessing the risk and benefit of a vaccination strategy for individual heart transplant patients, clinical efficacy, ongoing monitoring of rare serious adverse events, and data on vaccine immunogenicity should be taken into account.

Ixodes tick-borne borreliosis is a natural focal transmissive infectious multi-system disease featured with complex pathogenesis, which multiple aspects remain unclarified. The persistence stage during this infection associated with prolonged Borrelia presence in metastatic foci and repeated multiple dissemination is most complicated for clinical practice. It is assumed that the chronic process can be caused by an inadequate immune response associated with activated autoimmune mechanisms leading to emergence of permanent irreversible (degenerative and atrophic) changes in affected organs. Patients who experienced tick-borne borreliosis need dynamic observation for assessing disease prognosis providing a maintenance therapy. The purpose of the study was to evaluate an opportunity of using cellular immunity indices for predicting disease transition to a chronic course.Materials and methods. The study was carried out at the Medical Association of the Far East Branch of the Russian Academy of Sciences. Case report form data, serum and blood plasma samples collected from 22 patients aged 29–83 years old were examined. Immunological examination data from patients with ixodes tick-borne borreliosis (12–18 months after the onset of acute period) were analyzed. Specific IgM and IgG against Borrelia burgdorferi were determined by using the OMNICS diagnostic test system (St. Petersburg). Lymphocyte immunophenotyping was performed on BD FACSCalibur flow cytometer (Becton Dickinson, USA) by using doublelabeled monoclonal antibodies (Beckman Coulter, France).Results. A variability of activated peripheral blood lymphocytes was found in patients with tick-borne borreliosis evidencing about individual immune response. An imbalanced cellular immune response recorded in seronegative convalescents from tick-borne borreliosis, may be an indirect finding of ongoing Borrelia infection. Finding of specific serum IgG and IgM antibodies in convalescents at late stage coupled to impaired immune system is a warning sign presuming a risk to developing autoimmune reactions. Detection of specific IgM antibodies at late timepoint combined with increased immune cytotoxic potential may be referred to a marker of possible disease transition to chronic course.

Tularemia is an anthropozoonotic infection caused by Francisella tularensis. In clinical and sanitary-epidemiological practice, traditional diagnostics methods in tularemia are based on serological assays for detecting specific antibodies, allowing to diagnose it and estimate durability of patients’ immunity after vaccination. Previously, it was shown that specific serum antibodies in patients recovered after tularemia, unlike to those vaccinated with the live tularemia vaccine F. tularensis 15 NIIEG, can interact with specific epitopes on lipopolysaccharides isolated from strains of various subspecies — F. tularensis (Ft) and F. novicida (LPS Fn), while LPS Fn-specific immunoglobulins are lacked in the blood of vaccinated individuals. A set of experiments on identifying antibodies with similar specificity in laboratory animals of various species — mice, guinea pigs and rats with differed sensitivity to tularemia, administered with live tularemia vaccine strain as well as virulent F. tularensis strains to simulate vaccine-mediated and infectious processes, respectively was conducted. A methodical approach has been developed that allows to analyze humoral response in modelled infectious process in animals highly sensitive to tularemia such as BALB/c mice and guinea pigs that consisted of preliminary immunization with live tularemia vaccine followed by infection with virulent F. tularensis strains. It was shown that induction of specific anti-LPS Ft antibodies occured in these animal species, both after vaccination and infection with virulent strains. It was noted that, unlike guinea pigs and rats, mice both during vaccination and infection were characterized by significantly lower titers of LPS Ft-specific antibodies. However, no specific interaction between mouse serum and LPS Fn might be detected. Moreover, two types of immunoglobulins with different antigen specificities to the LPS Ft and LPS Fn epitopes were detected by dot-blot analysis in guinea pigs immunized with live tularemia vaccine, followed by infection with a virulent strain. In addition, antibodies to LPS Fn were also detected in the serum of rats infected with virulent, but not vaccine-based, F. tularensis strains. Thus, previous experimental data on the production of immunoglobulins with different antigenic specificity were confirmed in an experimental tularemia modelled in rats and guinea pigs that demonstrated a diagnostic significance and feasibility of using LPS Fn to confirm tularemia infection in humans.

Detection of the measles virus (MV) specific IgM antibodies in blood serum of patients is considered to be the main standard for the laboratory confirmation of measles diagnosis, the test being acknowledged by WHO. As it was demonstrated earlier the specific IgM antibodies as the marker of the acute MV infection were detected in 97.2–100% of blood serum samples from patients using the ELISA test-systems of the “capture” format (Microimmun Ltd. and Vector Best). In case when the ELISA test-system of the “indirect” format (Siemens, Germany) was used only 63.9% of these sera turned to be IgM positive. And on the contrary using the “indirect” format ELISA test-system Euroimmun, Germany, for detection of the MV specific IgM the false positive results were obtained.The aim of the study was the comparative evaluation of the different format ELISA test-systems used for the detection of the MV specific IgM antibodies in blood sera of patients and healthy adults collected in different geographic zones.Materials and methods. In total 108 serum specimens collected in 2015–2017 were studied: from healthy adult Guineans, residents of the Republic of Guinea (RG); patients aged 1–70 with the initial “infectious mononucleosis”, “infectious cytomegalovirus” and “rubella” diagnosis and taken from the bank of sera in the Subnational Measles/Rubella laboratory, StP Measles/Rubella RC in NWFR. The MV specific IgM antibodies were detected using the commercial ELISA test-systems “VectoMeasles-IgM” (Vector-Best, Russia) (“capture” format) and “Anti-Measles Virus ELISA IgM (NP)” (Euroimmun Medizinische Labordiagnostik AG, Germany) («indirect» format). The specific Epshtein-Barr Virus (EBV) IgM and IgG antibodies were detected with the commercial ELISA test-systems «DS-ELISA-anti-EBV-VCA-M», «DS-ELISA-anti-EBV-EA-G» and «DS-ELISA-anti-EBV-NA-G» (“Diagnostic Systems”, Russia).Results and discussion. The MV specific IgM antibodies were not revealed in the total of 108 blood serum samples from the healthy adults and patients, residents of the Russia and of the RG, with the “capture” format “VectoMeasles-IgM” ELISA test-system. The absence of the acute MV infection was also confirmed by the high measles immunity level (i.e. IgG MV antibodies titers) as well as by detection of the IgG antibodies of high avidity. At the same time in 6 of 108 total sera (5.5%) IgM MV antibodies were detected with the «indirect» format ELISA test system Euroimmun, Germany. In these 6 sera the EBV specific antibodies were also evidenced. The results obtained demonstrate the nonspecific reaction due to the possible reactivity with anti-EBV antibodies. Besides this the different percentage of the false positive reactions in sera from healthy adults, residents of the RG and residents of Russia was determined — 8.5±4.0% and 3.2±2.2% correspondently. Thus the preliminary results, and to get the final results for general conclusions increase of the total amount of the clinical specimens under studying is of extremely importance.

Abstract. Twenty healthy children were vaccinated, and then in a 5 years they were revaccinated with Priorix (measles, mumps, rubella vaccine), according to the national immunization calendar. The aim of the study was to observe and compare the shaping and maintenance of immunological memory. Specific IgM, IgA, IgG antibodies in serum, and their subclasses as well as antibodies avidity were tested by ELISA. It was demonstrated that IgM, IgG, and IgA antibodies shaped primary immune response to Priorix. Booster-effect was found in IgG and IgA antibodies in response to revaccination. Low avidity of antibodies in primary immune response changed to the high avidity (60–70%) antibodies of memory response to measles and rubella, and remained low for antimumps antibodies. IgG3 subclass was predominant, and IgG1 and IgG4 subclasses were involved in primary immune response. At the stage of immunological memory IgG1 was predominanted and IgG3 and IgG4 became minor.

Abstract. One hundred and seven children (45 girls and 62 boys) in the age of 20 months — 14 years old (mean 9,62±0,37) suffered from acute lymphoblast leukosis and solid tumors in history have been examined in the clinic of Research Institute of children infections of FMBA. The vaccination history was studied in all children and the titers of specific antibodies to measles and mumps viruses as well as immune status were determined. 83,8% and 85,4% of studied children had no protection against measles and mumps respectively or had low titers of antibodies. Immunological examination of these children conducted within 4 months after finishing of therapy revealed absence of immunodeficiency. It gave opportunities to vaccinate or revaccinate these children against mentioned infections. Fifty three children were immunized against measles and 47 — against mumps. Application of live vaccines was safe because majority of vaccinated against measles (81,1%) and mumps (82,9%) children had mild vaccination process. It was established that to increase immunological efficacy of vaccination using of polyoxidony during 5 days before vaccination and 5 days after vaccination is reasonable.