The review discusses issues related to genetic predisposition and resistance to tuberculosis. Genetic factors largely determine susceptibility to various diseases, including infections. The main focus is on the genes of the major histocompatibility complex and toll-like receptors. A number of genetic polymorphisms responsible for resistance and predisposition to tuberculosis and related clinical consequences are considered. Knowledge of molecular genetic biomarkers is necessary to identify risk groups and carry out predictive measures.

Determining the effectiveness and duration of humoral immunity to SARS-CoV‑2 is of great importance for the management tactics and forecasting of the COVID‑19 pandemic. However, it is important to understand that the high concentration of antibodies, which is characteristic of an acute immune response (including after vaccination), will not persist in its late stage of “memory”. The level of antibodies at the end of the acute phase of the immune response inevitably decreases, and then, having reached a certain limit, it stabilizes in most people.

The purpose of this study is to substantiate the threshold value of the “protective” level of antibodies to SARS-CoV‑2 when using the SARS-CoV‑2- IgG-ELISA-BEST reagent system of Vector-Best JSC, Novosibirsk, Russia.

The results of our study confirmed that 6–10 and even 18 months after the COVID‑19 disease and 6 months after vaccination, the antibody level positivity index (IP) remained relatively constant and comparable. Taking into account the risks of adverse reactions and complications caused by excessive immunization with repeated administration of the vaccine against a background of high antibody levels, it is advisable to focus on the average value of the level of antibodies of the late phase of the immune response, taking this level as the threshold value of “protective” immunity. The data obtained by us together with the results of foreign authors suggest that both infection with SARS-CoV‑2 and vaccination, in most cases, lead to the formation of long-term humoral immunity, which corresponds to the range of concentration of SARS-CoV‑2-IgG equal to IP=7,77 ± 1,64 or 102,63 ± 29,31 BAU / ml.

Determining the efficiency of the principal means of specific immunoprophylaxis in forming thepost-vaccinal immunity against the new coronavirus infection (СOVID‑19) is a very important and topical problem. Solving it involves the evaluation of the efficiency and choosing the laboratory diagnostics technique for an adequate estimation of the nature and the level of thepost-vaccinal immune response (PIR).

Research objectives. Evaluating efficiency of the humoral PIR involving theproduction of specific antibodies in patients vaccinated with ‘CoviVac’using quantitative andsemi-quantitative test systems developed by Russian and international companies.

Material and methods. The level of antibodies matching the principal known antigens of the SARS-CoV‑2 virus was measured. The probes were taken in a group of 103 persons 22–30 days after vaccination. The techniques used were the principal immunochemical ones (enzymelinkedimmunosorbent assay (ELISA) and chemiluminescent microparticle immunoassay (CMIA)). The nature and the level of the PIR in terms of these antibodies’ production was studied, and the adequacy of the diagnostic techniques applied was evaluated, wherefore the result convergence was studied, and the techniques’ cross-sensitivity and specificity were determined.

Results. Insufficient level of PIR in terms of producing antibodies against SARS-CoV‑2 after vaccination with‘CoviVac’was established. The levels of antibodies were found to be not highenough to ensure a reliable immunity against the Covid‑19. However, a highdegree of correlation between the results of different quantitative techniques for measuring theantibodies matching the S-protein and its BRD of the SARS-CoV‑2 virus was determined. Arather high convergence of the results of the quantitative and semi-quantitative techniques usedfor studying this type of antibodies was found.

Conclusions. The PR upon the vaccination with the ‘CoviVac’ is characterized by insufficientintensity level in terms of forming the long-living IgG antibodies with surface antigens of SARS-CoV‑2. In particular, the antibody count, which is generally considered capable of ensuringreliable protection, was not reached. Efficiency of the immunochemical testsystems used in this study is high enough and can provide an adequate estimate of the PIR after the vaccination with ‘CoviVac’ .

Serum ferritin is considered one of the predictors of severe forms of diseases and an increased mortality risk in patients with various diseases. However, the results of the studies performed to date are not heterogeneous and the usefulness of measuring serum ferritin in all inpatients, including those with COVID‑19, is being questioned. The study included the results of measuring serum ferritin in 761 adult patients, of which in the main group 634 were confirmed with COVID‑19, and 127 patients from the comparison group were hospitalized with other diagnoses. Differences in serum ferritin concentration in the main group (COVID‑19 “+”: survivors: Me 295.2, 95% CI: 353.8–449.1 µg/l, non-survivors Me 285.9, 95% CI: 309.9–628.9 µg/l) and in the comparison group (COVID‑19 “-”: survivors Me 267.2: 95% CI 268.2–526.0 µg/l, non-survivors Me 197.7, 95% CI: 110.3–529.0 µg/l) depending on the outcomes of the disease were not statistically significant. At the same time, in the cohort of the non-survivors, serum ferritin above 500 µg/l with COVID‑19 was 23.75 times more common, and in the cohort with a ferritin concentration above 1500 µg/l, 17.75 times more common than ferritin in the group of inpatients without COVID–19. Our results indicate the impracticality of measuring serum ferritin for all inpatients; however, they confirm the fact that selective measurement of serum ferritin in patients with severe course of diseases, especially infectious diseases, makes it possible to identify a category of patients with a high risk of developing hyperinflammation.

Technological capabilities make it possible to increase the diagnostic efficiency of quantitative immunochemiluminescent studies but require expanding the glossary of the clinical and laboratory consultation, taking into account metrological approaches to quality assurance. The variants of quantitative assessment of the “clinical uncertainty of assessing the patient’s condition based on a laboratory test”, formed taking into account the models of analytical quality requirements, are proposed. The clinical significance of the introduction of metrological approaches to ensuring and expressing accuracy in the practice of quantitative immunochemiluminescent studies in order to reduce risks and improve the safety of medical activities is demonstrated.

The article presents a clinical case of sepsis occurring under the “mask” of a lymphoproliferative disease.

The purpose of the study is to substantiate the need to analyze the entire set of laboratory and clinical data for the interpretation of the results of automated analysis of biological fluids.

Materials and methods. The study was conducted on the basis of the Clinical Regional Hospital No. 2 in Krasnodar (Russia). In dynamics, the ascitic fluid and blood samples of patient P. with suspected lymphoproliferative disease were analyzed on the Sysmex XN analyzer. The results of automated analysis of abdominal effusion were compared with the results of cytological studies, as well as other laboratory and clinical data. The informative value of leukocyte indicators of inflammation (neutrophil reactivity – Neut-RI, granularity of neutrophils – Neut-GI) obtained in the ‘CBC+Diff’ mode of the Sysmex XN analyzer for the diagnosis of sepsis has been established. According to the data obtained, the predictive value of the parameter of automated analysis of biological fluids HF-BF (high fluorescent mononuclear cells) in terms of differential diagnosis of benign/malignant nature of the effusion is probabilistic.

Conclusion. To verify the diagnosis, it is necessary to take into account the full range of indicators of automated analysis of biological fluids, comparing them with clinical data, as well as the results of hematological and biochemical tests.

Autoantibodies (aAb) are human immunoglobulins that can specifically bind to antigenic epitopes of molecules of their own body. Most of AATs have diagnostic value and are serological markers, as well as reflect the main mechanisms of loss of tolerance and inflammation in patients with autoimmune diseases. Indirect immunofluorescence (IIF) was the first method used to detect aAb. During the 1970s and 1980s, there was an evolution in qualitative methods with the introduction of immunoblotting or dot blotting, and second generation quantitative immunometric assays (radioimmunoassay,, enzyme-linked immunosorbent assay (ELISA), fluoroimmunoassay, immunochemiluminescence assay) were suggested. The growing number of aAbs, as well as the growing request for aAb research in general, has fueled the development of automated and multiplex testing. An example is the Chorus trio multi-parameter automatic station (Italy), which combines the ELISA method and the complement fixation reaction (CFR) on one platform. The advantages of this device include a large panel of tests, minimal labor costs, the ability to use the analyzer to perform analyzes in the “cito” mode, perform CFR tests in an automatic mode, high accuracy and reproducibility of results, and a compact design of the analyzer. The Chorus trio multi-parameter automatic station has been implemented into the routine practice of our laboratory for the diagnosis of autoimmune diseases as a confirmatory test. Thus, the effectiveness of new technologies, the possibility of automation and an increase in the speed and quality of testing, as well as the extensive information provided by innovative multi-parameter systems, will bring significant benefits for clinical laboratory diagnostics and clinicians.

Purpose of study. Identification of significant laboratory markers for the development of atherosclerosis (AS) of the carotid arteries (CA) in patients with obstructive sleep apnea syndrome (OSAS).

Materials and methods. 152 male patients were examined, 84 of whom, according to polysomnography (PSG), were diagnosed with OSAS. Diagnosis of AS CA was performed by triplex scanning. The complex of laboratory studies included the assessment of lipid metabolism, the concentration of highly sensitive C-reactive protein (hsCRP), interleukin‑1β (IL‑1β), interleukin‑6 (IL‑6) and interleukin‑10 (IL‑10) in blood serum.

Results. In patients with OSAS, a statistically significant increase in the complex of proatherogenic factors was found: hsCRP, pro-inflammatory cytokines, ratio of apoproteins and atherogenic coefficient compared with patients without OSAS despite the absence of differences in the severity of atherosclerotic lesions of the carotid arteries in these groups

Conclusion. The development of OSAS is associated with severe lipid metabolism disorders and activation of nonspecific inflammation, which determines an increased risk of atherosclerosis in this group of patients.

The material of this study is based on the results of archival examination data of 82 patients (No. 1–82) with various pathologies of the musculoskeletal system, who had a set of laboratory parameters necessary for analysis in their medical history that meets the requirements for creating an expert analytical system. In this work, for calculations and construction of a panel of ratios, we used a series represented by indicators of water-electrolyte exchange. Using the proposed method, the authors identified in personal laboratory data in patients with a high B-cross Lap index different complexes of B-cross Lap-associated connections, thereby differentiating various types of pathological disorders and offering them as images of typical pathological disorders that can be identified in personalized laboratory data. The authors note that the given and described complexes of B-cross Lap-associated bonds do not exhaust all possible variants of the distinctive features of the formation of an electrolyte ratio panel, but allow developers to start creating an archive of the knowledge base of images of disorders, which will be updated as it accumulates. clinical material and be used in their identification in the evaluation of laboratory data in each case. In the future, the authors plan to develop expert-analytical systems based on routine laboratory data that will be able to differentiate, in particular, the most common disorders of bone metabolism, as well as monitoring the effectiveness of therapy without the use of complex and expensive immunochemical methods in general hospitals.