The review discusses issues related to genetic predisposition and resistance to the new coronavirus infection including various factors: epidemiological, gender, ethnic and microbiome. The role of molecular genetic methods in the diagnosis of coronavirus infection is emphasized. The genetic factors largely determine the body’s susceptibility to various diseases, including infectious ones. The focus is on the genes associated with the production of interferons and enzymes that are responsible for anti-viral responses, as well as inflammatory reactions in the lungs. The first group includes genes IFNAR2 and OAS1, which control the production of antiviral proteins, while the second includes DPP9, TYK2 and CCR2, that control the behavior of monocytes. A number of other genetic polymorphisms responsible for resistance and susceptibility to infections and associated clinical consequences are discussed. The knowledge of molecular genetic biomarkers is necessary to identify risk groups, conduct predictive measures, including vaccination against COVID-19.

On March 11, 2020, the World Health Organization recognized the outbreak of the disease COVID-19 (Coronavirus Disease 2019) and the spread of the new coronavirus (SARS-CoV-2), which caused this disease, as a pandemic. The SARS-CoV-2 virus stimulates the production of antigen-specific antibodies for which commercial tests have been developed. The issue of diagnosing antibodies to SARS-CoV-2 became especially acute together with the beginning of mass vaccination of the population. Due to the fact that the reading of the result depends on the test format, it is necessary to understand how the antigenic target, the composition of the immunoglobulins and the way of expressing the result affect its interpretation. When analyzing the literature, it was found that with COVID-19, antibodies to the nucleocapsid antigen of SARS-CoV-2 can be detected somewhat earlier than antibodies to the spike antigen; virus-neutralizing antibodies are directed to the receptor-binding domain, seroconversion of immunoglobulins M and G begins simultaneously, and tests for total antibodies are potentially more sensitive due to the ability to capture antibodies with various features of the immune response. The problem of incomparability of quantitative results obtained on different systems is also noted. These factors must be taken into account when choosing a test for detecting antibodies to SARS-CoV-2, which will adequately solve a specific clinical and epidemiological problem.

The article reveals the need for a comprehensive laboratory assessment of testing for antibodies to SARS-CoV-2. In progress it is focused on the possible product of laboratory testing studies of false-positive results caused by the presence of human serum antibodies in that cross reacting with SARS-CoV-2 proteins. It is concluded that in order to reduce the proportion of false positive results of the study require the use of confirmatory test.

Assessment of the condition of a patient with coronavirus infection is an urgent problem in clinical practice. The parameter ’nucleated erythrocytes’ in a clinical blood test can be used in clinical practice as a marker of hypoxia in case of lung damage, since it objectively reflects the consequences of acute hypoxic stress in the patient’s body.

We studied changes in the parameters of the general (clinical) blood test in dynamics in outpatient patients with an asymptomatic course and a mild degree of severity of COVID-19. The study involved 67 patients. 30 men and 37 women were examined, their average age was 35 years. All the interviewed patients did not take specific antiviral drugs. Clinical manifestations were evaluated at the time of the survey on the 1^st and 7^th day from the day of receiving a positive PCR result. The parameters of the general (clinical) blood test were determined by flow cytometry in the CBC + 5Diff mode on a Unicel® DxH 800 hematological analyzer (Beckman Coulter, USA) in dynamics on the 1^st and 7th days of observation. The features of clinical manifestations in patients with an asymptomatic course and mild severity coincided with the data of other authors. Hematological changes were mainly characterized by changes in the number of white blood cells and their subpopulations. On the 7^th day of observation, there was a significant tendency to increase the number of white blood cells, lymphocytes, eosinophils, neutrophils and platelets within the reference intervals.

Objective. To demonstrate the capabilities of a comprehensive instrumental multimodal differential diagnosis of viral pneumonia in the context of the COVID-19 pandemic.

Material and methods. A clinical case of a patient with complicated viral pneumonia and a detailed description of the clinical picture, laboratory information, instrumental research data using minimally invasive interventions, followed by cytological and bacteriological examination, is presented.

Results. While the patient was in the hospital, a comprehensive study was performed with a targeted assessment of the state of the chest organs and using minimally invasive diagnostic methods. The signs of bilateral pneumonia (probably of viral etiology, possibly corresponding to COVID-19 infection) revealed by ultrasound and MDCT of the chest organs were the basis for patient’s hospitalization.

Conclusion. The multimodal instrumental approach allows to obtain a more complete picture of the pathological process in patients with viral pneumonia in a short time and minimizing radiation and determine the further tactical position in the treatment of this category of patients.

We conducted a laboratory examination of 83 people after vaccination against the new coronavirus with the use of the ‘Gam-COVID-Vac’ vaccine of National Research Centre for Epidemiology and Microbiology n.a. honorary academician N.F. Gamaleya (Moscow, Russia), in order to determine the presence of post-vaccination class G antibodies to SARS-CoV-2. The reagent system ‘SARS-CoV-2-IgG – ELISA-BEST’ (Vector-Best Co., Novosibirsk, Russia) was used. According to the manufacturer, the reagent system detects a pool of class G immunoglobulins synthesized to all antigenic determinants of protein S, including the RBD domain, which ensures the specificity of this method for assessing the post-vaccination immune response. The study involved 36 men and 47 women, with an average age of 48.40 ± 1.15 years. An interim analysis of the blood serum of 51 participants 21 days after the first dose of the vaccine showed the presence of IgG antibodies to SARS-CoV-2 in 45 (88.24%) people. After 42 days, all 83 (100%) people were found to have IgG antibodies to SARS-CoV-2 virus. It is advisable to continue the study to assess the dynamics of the level of postvaccinal antibodies for 6 months.

Measurement of platelet function by light transmission aggregometry (LTA) using a special device – an aggregometer requires significant time and is time-consuming. In this study, an automated LTA procedure was evaluated to establish the reference ranges. On the Sysmex CS-5100 analyzer, aggregation measurements were performed using several agonists at a certain concentration: ADP (2 µmol/L); arachidonic acid (1 mmol/L); collagen (2 µg/ml); ristocetin (1.2 mg/ml); epinephrine (5 µmol/L). For each agonist, the maximum and final aggregation, the Lag phase and the Area under the aggregation curve were measured. Reference ranges for a standard panel of activators were determined on 40 samples of healthy subjects in the concentrations recommended by the International Society on Thrombosis and Haemostasis. A standard panel of agonists can be used on Sysmex CS series analyzers: ADP, arachidonic acid; collagen; ristocetin, epinephrine, so these devices can replace specialized aggregometers or perform platelet aggregation where this investigation is not currently performed.

In medical literature bacteria of the genera Leptotrix and Leptotrichia are often considered as identical. Actually, they are antipodes, standing very far apart from each other in evolutionary terms. The confusion arose due to morphological similarity (filamentous forms). Leptotrix is a type of iron bacteria that live in neutral and slightly acidic fresh waters with a very low concentration of organic matter. The energy metabolism of leptotrix is strictly aerobic, oxidative, and chemoorganoheterotrophic (they oxidize divalent iron ions into trivalent iron to produce energy). Its clinical role has not yet been proven. Bacteria of the genus Leptotrichia are normal inhabitants of the oral cavity, urogenital tract and intestine of humans, they are strict anaerobes (some strains are microaerophiles). They cause inflammatory diseases in patients with immunosuppression of different genesis. However, assessment of their clinical role, when they are isolated from non-sterile habitats, requires the use of a skilled ecological approach, including knowledge of the dynamics of cell numbers, the dominance of a particular species, etc. It is absolutely unacceptable to diagnose the diseases caused by leptotrichia on the base of smear microscopy results (for example, smears of discharge from urogenital tract).

Ethylenediaminetetraacetic acid (EDTA)-dependent pseudothrombocytopenia is the phenomenon of a spurious low platelet count due to antiplatelet antibodies that cause platelet clumping in blood anticoagulated with EDTA. The aggregation of platelets in EDTA-dependent pseudothrombocytopenia is usually prevented by other anticoagulants, such as sodium citrate. EDTA-dependent pseudothrombocytopenia has never been associated with hemorrhagic diathesis or platelet dysfunction. In this article, a 2,5-year-old boy with EDTA-dependent pseudothrombocytopenia is presented because of rare presentation. We report that EDTA can induce platelet clumping, and thus spuriously low platelet counts. However, aggregation of platelets was not detected in blood samples with sodium citrate, and platelet count was normal.

The analysis of the informativeness of traditional laboratory markers was performed by verification of individuals with the laboratory features of chronic kidney disease (blood creatinine level exceeding the reference range upper limit) among 142,494 people, who underwent laboratory tests during dispenserization and medical examination during 2015–2019. A stable growth of population groups characterized by preclinical hypercreatininaemia was observed, suggesting the increase of chronic kidney disease rate. Meanwhile the frequency of this population group, corresponding to the obtained values, is considered to be a cardiovascular cohort (primarily affected by chronic cardiac failure) in ‘Chronic kidney disease’ clinical recommendation (2019). Our results clearly demonstrate the cardiorenal continuum. Obtained data can be used in the resource support of the health care system calculation.

In this paper, the metabolic syndrome (MS) is considered as a manifestation of an excessive adaptive response of the body, which underlies premature aging. It is relevant to search for new early markers of MS formation in LPA in the context of modern ideas about the role of universal mechanisms of adaptation and stress-induced premature aging in its pathogenesis. The data obtained by the authors allow us to consider the relative androgen deficiency as a predictor of the formation of MS in LPA. The results of the study demonstrate that the levels of triiodothyronine and DHEAS serve as early markers of the formation of MS, while the testosterone/estradiol ratio is a universal laboratory indicator of accelerated aging of the body and MS.