Natural killer cells (NK) are innate immune lymphocytes produced in the bone marrow. Isolation of NK cells as a separate population of lymphocytes is related to discovery of their ability to induce the death of tumor cells without prior sensitization. In this review, an attempt was made to systematize the numerous data on the biology of NK cells presented in the literature. The authors consider the stages of NK cells` differentiation from a common lymphoid progenitor (CLP) in the bone marrow, describe two functionally different populations of mature NK cells – CD56brightCDl6- and CD56dimCD16+. In addition, the role of cytokines and chemokines in the development of NK cells is discussed. The review includes data on the spectrum of molecules expressed by NK cells: adhesion molecules (LFA-1, LFA-2, LFA-3; αMβ2, αXβ2, L-selectin, VLA-4, VLA-5; PECAM-1; CEACAM-1), cytokine receptors (IL-1R, IL-2ra, IL-2Rb/IL-2Rc, IL-6Rα, IL-7Ra, IL-8R, IL-10R, IL-12Rβ1, IL-15ra, IL-18R, IL-21ra, IFNGR2, TGFBR, c-Kit, CXCR1, CXCR3, CXCR4, CCR4, CCR5, CCR6, CCR7, IChemR23, CX3CR1), as well as receptors that regulate the activity of NK cells (LILRB1, LILRB2, LILRB4; KIR2DL1-5; KIR2DS1-5; KIR3DL1-3; KIR3DS1; NKG2A, NKG2C, NKG2D; Siglec7, Siglec9; CD16; NKRP-1; TIGIT; TACTILE; NKp30, NKp44, NKp46, NKp80; LAIR-1; PD-1; TIM-3; 2B4; TLR1-9). The authors also examine the mechanisms of implementing cytotoxic activity by NK cells, including cytotoxicity, via expression of MHC-I-specific receptors, CD16 Fc receptors, receptors and ligands of apoptosis (Fas-FasL and TRAIL-TRAILR) as well as other receptors. The review describes in detail the structure of immunological synapse between the NK cell and target cell, receptor interactions, and the role of the cytoskeleton in its formation. The data are summarized on the variants of exocytosis of lytic granules by NK cells, including complete or partial fusion of vesicles with the plasma membrane, exocytosis of vesicles containing perforin and FasL, and the formation of microvesicles containing granzyme B. The review also describes data on ability of NK cells to maintain activated state for a long time, as well as to maintain contact with several targets at the same time. In addition to the functions inherent in natural killers as cells of innate immunity, the authors point out their ability to exhibit the features of cells of adaptive immunity. In general, a variety of mechanisms that regulate the activity of NK cells may complement the specific functions of lymphocytes, thus making the immune system more efficient.

The data obtained during previous epidemics caused by coronaviruses, and current pandemic indicate that assessing the role of certain immune interactions between these viruses and the microorganism is the main pre-requisite for development of diagnostic test systems as well as effective medical drugs and preventive measures. The review summarizes the results of studying patho– and immunogenesis of SARSCoV, MERS-CoV, and SARS-CoV-2 infections. These coronaviruses were proven to suppress development of adaptive immune response at the stage of its induction, affecting the number and functional activity of lymphocytes, effectors of cellular immunity, causing impairment of lymphopoiesis, apoptosis and «depletion» of these cells, thus leading to longer duration of the disease and increased viral load. Information about the role of cellular immunity in development of immune response to coronaviruses is presented. It was proven that the causative agents of SARS, MERS and COVID-19 trigger adaptive immune response in the microorganism according to both humoral and cellular types. Moreover, the synthesis of specific immunoglobulins does not yet point to presence of protective immune response. Activation of the cellular link of immunity is also important. A high degree of antigenic epitope homology in SARS-CoV, MERS-CoV and SARS-CoV-2 is described, thus suggesting an opportunity for cross-immunity to coronaviruses. The review addresses issues related to the terms of specific memory immune cells to SARS-CoV, MERS-CoV and SARS-CoV-2, and their role in providing long-term protection against these infections. Given that specific antibodies to SARS and MERS pathogens persisted for a year, were often not detected or briefly registered in patients with mild and asymptomatic infections, we can talk about important role of the cellular immune response in providing immunity to these coronaviruses. It was shown that, in contrast to antibodies, the antigen-specific memory T cells were registered in patients with SARS virus for 4 to 11 years, and Middle East Respiratory Syndrome – up to two years. Further research is needed to determine presence and number of memory T cells in COVID-19. A comparative analysis of data obtained during previous epidemics with respect to formation of adaptive immunity to coronaviruses. Description of proteins and epitopes recognized by human T lymphocytes will be useful in monitoring immune responses in COVID-19 patients, as well as in developing informative tests to study T cell immune response to SARS-CoV-2 and new preventive drugs.

Cell infiltrate is a morphological substrate of immunoinflammatory rheumatic diseases. The systemic wide progressive disorganization of loose fibrous connective tissue is accompanied by the loss of tolerance with its own autoantigenes, activation of macrophagal-monocyte cells and autoreactive clones of T and B lymphocytes. Hyperproduction of pro-inflammatory chemokines and cytokines, local adhesive ligandreceptor interactions, endothelial reaction and angiogenesis contribute to the formation of cell infiltrate, ectopic lymphoid structures and GZT-granulomas in situ. The autoimmune response is the result of successive systemic and local molecular cellular events in which the mechanisms of congenital and adaptive immunity are involved. When interpreting immunopathogenesis of rheumatic diseases, all models and schemes adopted in the field of fundamental immunology are used. This is a model of MHC-restrictions, a model of molecular mimicry, or cross of the antigen presentation, a model of disrupting central or peripheral tolerance to auto-antigens, a model of candidate “triggers” of autoimmune and autoinflammatory processes, a model of associations of alleles MHC I and II classes with specific, nosologically unique, rheumatic diseases.

The present review considers the role of mast cells (MC) and tryptase levels in various pathological conditions in children and adults. The main causes of hypertryptasemia are presented, as well as a list of the most important stimuli that can cause activation of MC. Cliical allergologists should focus their clinical practice on the patients with anaphylaxia and suspected MC activation syndromes. Moreover, hypertryptasemia (> 20 ng/ml) is considered an additional diagnostic criterion for systemic mastocytosis, according to the WHO recommendations. As a rule, the level of tryptase is constantly elevated in most patients with systemic mastocytosis, whereas it is undergo changes in acute IgE-mediated hypersensitivity reactions. In cases of anaphylaxia, tryptase concentration should be determined in the patients during the first hours following onset of acute allergic reaction, and 24-48 hours later. Recommendations are given for determining tryptase levels in blood serum of the patients (basal and peak values), and algorithms are provided for usage of these indexes in various diseases. The article also provides the assessed threshold values of tryptase when diagnosing anaphylaxia, MC activation syndromes, and a novel disorder – alpha-tryptasemia. In the diagnosis of hereditary alpha-tryptasemia, as well as MC activation syndromes (primary and secondary), clinical manifestations in the patient and time dynamics of tryptase levels should be taken into account. The accumulated experience allowed to consider, first of all, frequency of severe allergic reactions (most often as anaphylaxia) in the patients with suspected MC activation syndromes. The syndrome of MC activation is characterized by excessive release of their granule contents without signs of clonal proliferation, which in many cases may be due to gene allele duplication, especially, TPSAB1 α-tryptase gene. For patients with hereditary alpha-tryptasemia, the most characteristic manifestations are represented by vegetative-vascular dystonia (orthostatic tachycardia), joint hypermobility, etc. Hence, determination of tryptase level (especially in time course) should be given more attention in the practice of clinicians. Difficulties with interpretation of the results arise in cases when tryptase concentration remains within normal range (up to 11.4 ng/ml), and the patient has clinically evident mastocytosis, or MC activation syndromes. If the patient has a history of anaphylaxia, especially after bites of hymenoptera insects, the TC activation syndromes should be excluded.

Surgical resection was the main approach to cancer therapy, often supplemented by radiation and chemotherapy. The effectiveness of such complex treatment in many cases remains low. In this regard, there is an urgent need to search for new compounds that have selective cytotoxic activity against tumor cells and do not damage normal tissues of the organism. The review discusses mechanisms of antitumor action of cationic antimicrobial peptides (AMPs) of the cathelicidin family - human α-helical cathelicidin (LL-37), and a peptide with β-hairpin conformation – protegrin-1 (PG-1) on lung, breast, pancreas, prostate, squamous skin cancer cells, oral cancer, stomach, ovarian, colorectal cancer, melanoma, leukemia, lymphoma, glioma and neuroblastoma cells. An opportunity of antitumor and pro-oncogenic actions of the peptides and an interplay of these effects with mmunomodulatory action of AMPs on tumor-associated macrophages, natural killer cells and T-lymphocytes is discussed. Possible mechanisms of LL-37 and PG-1 selective action upon tumor cells are presented, including the interaction of LL-37 with G-protein-coupled receptors: the N formylpeptide-2 receptor (FPR2), CXC chemokine-2 (CXCR2), Mas-related gene X2 (MrgX2), purinergic (P2Y11), epidermal (EGFR/ErbB1, ERBb2), insulin-like (IGF1R) growth factors, ligand-gated ion channels (LGIC) and Tolllike (TLR) receptors, with expression varying significantly in different types of tumors, as compared to normal tissues. An increase in the level of LL-37 secretion and expression of its CAMP gene are associated with progression of lung adenocarcinoma, breast, pancreas, and prostate cancer, ovarian cancer, melanoma, and squamous cell carcinoma of the skin. In contrast, CAMP expression and LL-37 secretion are significantly reduced in gastric cancer cells, oral squamous cell cancer, colorectal cancer, leukemia, lymphomas, gliomas, and SH-SY5Y neuroblastoma. Therefore, therapeutic effects of LL-37 can only be used for specific types of tumors. The mechanisms of action of PG-1 on tumor cells are still poorly understood, although the available data indicate that protegrin exhibits a more unidirectional effect, i.e., it damages cell membranes. Protegrin-1 and LL-37 can synergistically enhance the antitumor effects of chemotherapy drugs and have a more pronounced effect on tumor cells, than upon normal cells. Natural AMPs appear to be promising candidates for the role of new antitumor agents, which are also active against malignant metastatic, recurrent multidrug-resistant tumors. On the other hand, peptides such as LL-37, in some cases, exhibit properties that can be considered pro-oncogenic, which indicates a need for further detailed studies on the molecular mechanisms of their action on tumor cells.

Transfusions of blood provide essential therapeutic measures in a number of pathological conditions. However, when carrying out blood component therapy, it is important to consider probability of post-transfusion complications. Most of them are immune-mediated side effects. The unfavorable consequences of blood transfusions can manifest at long-range time periods, and pathogenesis of these phenomena may be associated not only with the presence of alloantibodies. They may be caused by alloimmunization to HLA antigens, leukocyte factors, including cytokines, products of leukocyte degranulation, as well as storage-related erythrocyte damage («storage lesion»), immunomodulatory properties of extracellular vesicles or microparticles derived from blood components, and other factors. Despite significant number of publications on this issue, a lot of unresolved issues still remain, concerning transfusion-related effects of blood components on the immune system of recipients. The review article provides the results of current studies in this area. We present and discuss the results of current studies and the features of transfusion-mediated immunomodulation (TRIM) revealed over recent years, when transfusing different blood components. The role of plasma factors, microparticles, platelets and erythrocytes, HLA sensitization and microchimerism in the development of TRIM is highlighted, the data on occurrence and clinical features of TRIM in perioperative period are presented. A separate section of the review provides information about recent clinical studies, devoted to the issues of TRIM in different clinical cohorts, including newborns, patients with malignant neoplasms, immunocompromised patients after heart and vascular surgery. The data on TRIM incidence in the patients with exhausted immune system due to previous disease or treatment, severe comorbidity, extensive surgical thoracic/abdominal intervention and artificial circulation are also in scope. As based on the studies performed, the role of distinct measures, e.g., washing of erythrocyte concentrates, leukodepletion, and gamma irradiation are discussed in view of potential TRIM prevention. The results of published research do not allow us to draw definite conclusions about the effects of blood component transfusion on the immune system of recipients with respect to differences between the studied groups of patients, characteristics of the studied disorders and clinical situations, diversity of hemocomponents, as well as varying standards of transfusion therapy adopted in different countries. However, the systematic literature review may provide some guidance in transfusion-mediated immune modulation.

The aim of current study was to compare profiles of T cell subsets in the patients with ankylosing spondylitis (AS) who received different modes of genetically engineered biological therapy (GEBT). The research involved 58 patients aged 20 to 58 years diagnosed with AS and treated with anti-TNFα and antiIL-17 drugs, as well as those receiving common anti-inflammatory therapy. The AS diagnostics was based on the modified New York criteria. Disease activity was assessed by means of nomenclature approved by the Assessment of Spondyloarthritis International Society and Outcome Measures in Rheumatology. 45 healthy people aged 18 to 57 were included into the control group. Peripheral blood T cell subsets were analysed by multicolor flow cytometry. It was found that the T lymphocyte subpopulation profiles in AS patients showed significant differences depending on the therapy type. First, T lymphocyte counts were decreased in AS patients receiving traditional anti-inflammatory therapy, whereas relative numbers of T cells with high levels of effector potential and cytokine secretion were increased. Negative correlations between the levels of effector memory and pre-effector cytotoxic T cells and other laboratory and clinical indexes of inflammatory activity in AS may reflect lower efficiency of traditional therapy. Next, the levels of main T cell subsets in AS patients during antiIL-17 therapy fully corresponded to the control values. However, based on numerous correlations between immunological and clinical laboratory parameters, it was concluded that anti-IL-17 therapy had an inhibitory effect on the joint inflammation activity, while the state of T cell subsets was mainly dependent on standard anti-inflammatory therapy. The most pronounced changes in T cell subsets were found in AS patients during anti-TNFα therapy was associated with decreased effector potential of Th cells and cytotoxic T lymphocytes. At the same time, the lowest frequency of extraskeletal manifestations was found in AS patients treated with anti-TNFα drugs. Finally, the higher efficiency of GEBT, compared with conventional methods of therapy, is determined by the effects upon immune targets of AS pathogenesis which manifested, e.g., by changes in the T lymphocyte subpopulation profile. Moreover, usage of anti-TNFα versus anti-IL-17 inhibitors was associated with greater effect upon phenotypic profile of T cells.

Psoriasis is considered an autoimmune disease with a predominantly cellular mechanism for the development of disorder. Studies in immune pathogenesis of psoriasis were performed either in animal model, which is not just similar to humans, or the data were obtained in patients by means of skin window method, which is traumatic, or by examining venous blood. However, it is difficult to discern parameters of the local immune response in venous blood samples. We have attempted to find an adequate method which would be convenient both for the patient and for the researcher, in order to assess local immune processes occurring in the skin affected by psoriasis. We examined 20 patients with a verified diagnosis of psoriasis, the average age was 44.3 years. The control group included 15 healthy adults, with average age of 46.6 years. Capillary blood was taken by fingerprick, whereas, in psoriatic patients, the samples were taken near the psoriatic lesion at a final volume of 400 μL in two microvettes. Venous blood (3 mL) was taken from the cubital vein into a vacuum tube with EDTA. Clinical analysis of venous and capillary blood was performed in automated hematological analyzer. Immunophenotyping was performed by four-color staining of whole capillary and venous blood followed by lysis of erythrocytes. Cytofluorometry was performed using techniques and reagents from BD Biosciences (USA). Plasma cytokines were determined by multiplex approach (MagPix, BioRad, USA). Upon clinical analysis of blood, the difference between capillary and venous blood was not found, either in healthy group, or among patients with psoriasis. In healthy people, the subsets of mononuclear cells, did not differ between venous and capillary blood. The samples of capillary and venous blood in the patients with psoriasis showed significantly increased levels of double-positive lymphocytes (CD45RA+/CD45R0+), B lymphocytes and NKT lymphocytes (both for relative and and absolute values). A significant increase in the percentage of naive T lymphocytes, activated helpers (Thact) and Treg, as well as B1 cells and Breg, and a significant decrease in B2 lymphocytes was registered in capillary blood of the patients with psoriasis. In venous blood samples from psoriatic patients, only a significant increase in Thact, Treg, and Breg was revealed. In the capillary blood of patients with psoriasis, we found a significant increase in the levels of non-classical M2 monocytes and inflammatory Minfl monocytes, and a decrease in classical M1 monocyte levels; in venous blood of psoriatic patients, only an increase in inflammatory Minfl monocytes was revealed. In capillary blood, all the studied cytokines in psoriasis patients significantly exceeded the levels of corresponding cytokines in healthy controls, except of IL-10. The levels of this cytokine did not differ from healthy group. In venous blood, the levels of most studied cytokines in the group of patients with psoriasis did not differ from the group of healthy ones. Approximately two-fold increase was revealed for IL-4, IL-21, IL-23 and TNF. First, the subsets of mononuclear cells and the cytokine profile of capillary and venous blood of healthy people did not differ significantly. Secondly, our proposed method for determining the subsets of mononuclear cells and capillary blood cytokines profile from the area of psoriatic lesions may be used to monitor local immunity in the patients with psoriasis. This approach is significantly less traumatic than the skin window method and more informative than the studies of venous blood.

Urticaria is a serious medical and social problem due to its high prevalence, lack of unified approaches to diagnosis and treatment, with high financial costs for therapy and rehabilitation. Long-term recurrent course of the disease, resistance to traditional methods of therapy lead to a significant decrease in the quality of life of patients with chronic urticaria. Itching accompanying this disease leads to deterioration in the patient’s general well-being, frequent sleep disturbances and, as a result, significant decrease in working capacity. Up to the present moment, etiopathogenesis of urticaria is a complex challenge due to the multivector nature of cytokine response, interference of protides of the complement system, patterns of kininbradykinin interference, peculiar expression of the immune response. The problem of current population is lipotrophy – chronic, heterogeneous, cytokine mediating, progressive inflammatory disease attributed by abnormal accumulation of excessive adipose tissue. Adipose tissue, being a sporadic organ of endocrine system secretes multiple hormone-like substances, mediators, cytokines and chemokines which have been given a common name, i.e., adipokines or adipocytokines. True signs of destructive parenchymal changes of liver in the form of increasing bilirubin and AST, decreasing level of vitamin D in patients with chronic recurrent urticarial in presence of obesity have been revealed during the study performed. The action of cytokines, as mediators of intercellular interaction is closely related to the physiological and pathophysiological responses of the body with modulation of both local and systemic defense mechanisms. It is assumed that the cytokine status of patients with chronic urticaria is dominated by cytokines that increase allergic inflammation of the skin. Analysis of 12 T regulatory biomarker concentrations revealed increased concentrations of IL-10, IL-19, IL-20, IL-27, IL-35, IFNλ2 and IFNλ1 in blood serum of patients with chronic urticaria. It was found that in the group of patients with chronic urticaria and increased body mass index (BMI), the level of all investigated T regulatory cytokines is lower than in the patients with normal BMI, except for IL-10. Decreased levels of biologically active IFN I (α/β) and, especially, IFN II (γ) types of blood leukocytes in patients with chronic urticaria were revealed. The levels of 12 Treg cytokines were determined in blood serum of patients with chronic urticaria, showing trend for imbalance of Treg cytokines: IL-10, IL-19, IL-20, IL-27, IL-35, IFNλ2 and IFNλ1.

Chromosomal pathology is one of the most common causes of congenital malformations. The CATCH-22 symptom complex is most often associated with a microdeletion of chromosome 22, upon detection of which it is customary to diagnose DiGeorge syndrome, a known primary immunodeficiency or syndrome of innate errors of immunity. According to our data on the frequency of occurrence among all chromosomal abnormalities, DiGeorge’s syndrome takes second place in the Sverdlovsk region after Down’s syndrome, but its diagnosis is not simple due to varying severity of clinical manifestations, as well as different forms of the chromosome 22 defects. Along with several typical variants of 22q11 microdeletions, there duplications of critical regions are also reported, accompanied by immunodeficiency and other symptoms of CATCH-22. The effectiveness of diagnosing chromosomal abnormalities both in pre- and postnatal period largely depends on the grouping criteria of the patients with suspected chromosomal abnormalities, and on the methods used to identify hereditary pathology. In our study, we analyzed and compared the results of studies of 23 patients with various rearrangements of the 22q11.2 region, which were observed by a geneticist and clinical immunologist. The paper presents data on the polymorphism of phenotypes associated with rearrangements of the 22q11.2 region with an analysis of pathomorphological manifestations depending on the type of structural anomaly, i.e, del22q11.2, or dup22q11.2. The results of analysis demonstrate importance of different diagnostic options for laboratory studies of microdeletion and microduplication syndromes associated with immune-dependent pathology. We also compared the results of molecular genetic diagnostics and phenotypic manifestations in deletions and duplications of the 22q11.2 region. To identify the rearrangements of 22q11.2 region, two different methods were used – Prenatal BoBs and multiplex ligase-dependent probes’ amplification (MLPA). In particular, the both methods were used in the same patient to verify diagnosis, thus enabling to show differences in their efficiency. It was concluded that 22q11.2 deletion syndrome exhibits wide heterogeneity in phenotypic traits: neurological and immunological manifestations, anomalies in musculoskeletal development and internal organs, skull deformities and facial dysmorphia. Each clinical case was unique, requiring careful analysis of clinical manifestations. It is necessary to have a wide range of laboratory options for molecular genetic verification of the diagnosis.

Traumatic brain injury is the most common cause of death and disability in young people including sport athletes and soldiers, people under 45 years of age in the industrialized countries, representing a growing health problem in developing countries, as well as in aging communities. Treatment of the latter is a serious challenge for modern medicine. This type of injury leads to many kinds of disorders and, quite often, to disability. These issue require development of new methods for brain trauma treatment. The new approach to brain trauma treatment was studied in murine experiments. In particular, sodium salt of deoxyribonucleic acid (DNA) was used. This preparation is a drug known as a mixture of peptides with immunomodulatory effect which is widely used for different kinds of therapy. Derinat, a sodium salt of DNA, isolated from the caviar of Russian sturgeon, is a proven immunomodulator for treatment of diseases associatd with reactive oxygen species (ROS), including brain ischemia-reperfusion (IR) injury. Here we show that treatment with Derinat exert neuroprotective, anti-oxidative, and anti-inflammatory effects in experimental model of traumatic brain injury (TBI) in rats. Intraperitoneal injection of Derinat several times over 3 days after TBI showed less pronounced damage of the injured brain area. Immunohistochemical study showed that the Derinat-induced morphological changes of microglia in cerebral cortex and hippocampus 7 days after TBI. TBI-induced accumulation of 8-oxoguanine (8-oxoG), the marker of oxidative damage, was significantly attenuated by Derinat administration, both on 7^th and 14th day after TBI. To investigate cellular mechanism of anti-inflammatory effects, the primary cultures of murine microglia supplied with ATP (50 M and 1 mM), as a substance released at injured site, were used to mimic the in vitro inflammatory response. Derinate treatment caused an increase of glial levels of mRNAs encoding neurotrophic factor (GDNF) and nerve growth factor (NGF) in the presence of ATP, whereas tissue plasminogen activator (tPA) mRNA was inhibited by ATP with or without Derinat. Interleukin-6 (IL-6) mRNA expression was not affected by ATP but was increased by Derinat. Both mRNA and protein levels of ATP-induced TNFα production were significantly inhibited by Derinat. These results partially contribute to understanding mechanisms of immunomodulatory effects of DNA preparations in traumatic brain injury.

Natural killer cells (NK cells) are innate immunity lymphocytes. NK cell differentiation is controlled by the cellular microenvironment and locally produced cytokines, including IL-2, IL-15 and IL-18. NK cells are present in various tissues, forming pools of tissue-resident NK cells, e.g., decidual NK cell pool. Peripheral blood NK cells (pNK cells) are considered a supposed source of cells for decidual NK cell differentiation. In the uterus, NK cells contact with trophoblast cells, which can affect their phenotype. Contribution of trophoblast cells and IL-2, IL-15 and IL-18 cytokines to the pNK cell phenotype regulation is scarcely studied. In this regard, the aim of our research was to evaluate the effect of trophoblast cells on the phenotype of pNK cells when cultured in medium with IL-2, IL-15, and IL-18. We used mononuclear cells obtained from peripheral blood of healthy non-pregnant women at their reproductive age, with regular menstrual cycle (n = 21). Mononuclear cells were cultured in presence of IL-2, and either of cytokines regulating NK cell differentiation (IL-15, or IL-18). JEG-3 cells were used as trophoblast cells. We evaluated expression of CD45, CD3, CD56, CD14, KIR3DL1, KIR2DL3, KIR2DL4, KIR2DS4, NKp44, CD215, CD122, CD127, NKG2D, KIR2DL1, NKG2C receptors by pNK cells. It was found that pNK cells cultured in presence of trophoblast cells (JEG-3 cell line) were characterized by lower intensity of CD56 receptor expression, compared to pNK cells cultured without trophoblast cells. These changes were detected upon culturing both in medium supplied by IL-15, and with IL-18. A reduced number of NKG2C+ pNK cells was detected in presence of JEG-3 trophoblast cells, compared to NK cells cultured without trophoblast cells in medium with IL-15. The detected changes in the CD56 and NKG2C expression by pNK cells in presence of trophoblast cells proved to be opposite to those previously detected for NK cells derived from NK-92 cell line. Along with trophoblast cells, the monocytes isolated among mononuclear cells and being affected by cytokines, can apparently influence the phenotype of pNK cells in the model system used. Since monocytes/macrophages are present in decidua, further research is required to study the effect of cytokines and cellular microenvironment, including monocytes, on pNK cells.

Microflora of the oral cavity forms a biofilm that induces response of immune system at the mucous membranes. Transition to periodontal lesion is provided by certain classes of resident mucosal immune cells and inflammatory/immune cells migrating to the periodont. In periodontal diseases, Th1, Th2, Th17, Treg are detected. T regulatory cells (Tregs) are proven to comprise the main anti-inflammatory cell population. Th17 cells and Treg cells play an important role in osteoclast differentiation. IL-17 secreted by Th17 cells affects osteoclastogenesis and may induce macrophages to enhance the local inflammatory response. In this regard, the aim of our work was to identify the local immune cells in oral cavity which are associated with severity of chronic generalized periodontitis. The oral cavity cells from 58 persons aged 38-65 years of both sexes in their mature age with a diagnosis of «chronic periodontitis» were examined by means of flow cytofluorometry. When determining levels of CD64⁺CD16⁺CD14- neutrophils in the patients with periodontitis of different severity, a statistically significant increase of this cell population was revealed upon development of this disease. In mild cases of periodontitis, a significant increase of relative CD64+CD16+CD14-  neutrophil contents was revealed (Me = 36.16%, p < 0.05) compared to the control group (Me = 7.7%, Q_0.25 = 2.4%, Q_0.75 = 12%). When assessing relative numbers of CD14⁺ monocytes in periodontitis of various severity, we revealed a significant increase in the number of these cells in severe cases. When studying levels of regulatory T lymphocytes (CD4⁺CD25⁺CD127^low) in periodontitis of different severity, we revealed significantly decreased amounts of this cell population during development of the disease. In mild cases of periodontitis, a decreased level of CD4⁺CD₂₅⁺CD127^low cells (p < 0.05, Me = 1356 cells/ml) was revealed, as compared with control group (Me = 10666 cells/ml). Although the concentration of CD4⁺CD25⁺CD127^low (Me = 4709 cells/ml) in the patients with moderate periodontitis was higher than the values in milder cases, the range of the main values was comparable and lower, than in control group. In severe periodontitis, a significantly decreased concentration of regulatory T lymphocytes was revealed (Me = 2637 cells/ml). These results confirm the anti-inflammatory regulatory function of Tregs. Understanding the osteo-immune mechanisms of bone remodeling control will help to understand the pathophysiology of accelerated bone loss observed in severe chronic periodontitis.

The new coronavirus SARS-CoV-2 has become a global challenge to medicine and, in particular, laboratory diagnostics. The study of the antibodies’ level to SARS-CoV-2 can be used as a confirmation test in the diagnosis of a disease, but it becomes of paramount importance in assessing population immunity resulting from a disease or vaccination, as well as in selection of convalescent plasma donors. The kits developed in our country and abroad for detecting antibodies to the SARS-CoV-2 virus differ both in the methods of testing and in the used coronavirus antigens to which the antibodies are directed. The aim of this study was to compare the diagnostic sensitivity and specificity of five kits for the detection of IgG antibodies to the SARS-CoV-2 virus, based on different diagnostic methods. Serum samples from 137 COVID-19 convalescents and 166 donors of blood and its components were examined. The control group consisted of 50 blood sera collected at the beginning of 2019 and 19 sera collected in 2018 (before the advent of the SARS-CoV-2 virus) and stored at -70 °C. Testing was carried out in analytical systems: rapid test “COVID-19 IgM/IgG Rapid Test (Colloidal Gold)” (China), on an automatic immunochemical analyzer Abbott Architect™ i2000 and kit “SARS-CoV2-IgG” (Abbot, Chicago , IL USA), by the chemiluminescence method using an automatic analyzer of the CL series and kits of the “Mindray” company (China) “SARS-CoV-2 IgM” and “SARS-CoV-2 IgG” and by the enzyme immunoassay method on the kits of the companies “Diagnostic Systems” Ltd (Russia, Nizhny Novgorod) “DS-IFA-ANTI-SARS-CoV-2-G”, “Xema” Ltd (Federal State Budgetary Institution “National Medical Research Center of Hematology” of the Ministry of Health of Russia) “SARS-CoV-2-IgG-IFA” and “Vector-Best” CJSC (Russia, Novosibirsk)” SARS-COV-2-IgM-IFA-BEST” and “SARS-COV-2-IgG-IFABEST”. When comparing the results of testing 137 plasma samples on the Vector-Best and Mindray kits for IgG antibodies, 127 samples were positive, 7 samples were negative on both kits, the discrepancy was 2.2%. In the study of IgM antibodies, 32.1% were positive, and 52.6% were negative in both kits. The discrepancy rate was 15.3%. Out of 166 samples, 1 serum (0.6%) was negative in 5 kits. On the Mindray kit, IgG antibodies to the antigens of the SARS-CoV-2 virus were detected in 165 samples (99.4%), on Vector-Best – in 164 sera (98.8%), on Diagnostic systems – in 151 (90.96%), on Xema – in 154 (92.8%), and on Abbott – in 155 samples (93.4%). At the same time, 135 (81.33%) samples were positive in all kits, while 30 samples had discordant results (18.07%), and in 9 sera, specific IgG was not detected in 2 or more kits. ROC analysis revealed a high diagnostic value of all tested kits (AUC from 0.908 to 0.998), which indicates a high quality of the separation model of positive and negative samples (p < 0.001). With the cut-off set by the manufacturers, the sensitivity and specificity ranged from 82.8% and 93.3% for the Diagnostic Systems kit to 99.4% and 95.8% for the VectorBest kit. The calculated correlation coefficients were higher between kits with a similar composition of the antigen used in the kits; therefore, it is better to monitor the dynamics of antibodies by diagnostic kits from the same manufacturer.

Primary immunodeficiencies is a group of diseases resulting from a variety of genetic defects. At the moment, more than 300 immunodeficiencies are known, most of which negatively affect the quality and duration of life, leading to deaths in the first year of a child's life. The most severe and at the same time quite frequent are defects in cellular immunity. It is currently known that the incidence of clinically significant T lymphopenias is 1: 4000 live newborns, and the incidence of clinically significant cellular primary immunodeficiencies is 1: 10000 live newborns. Despite the extensive treatment options for these diseases, patient survival is low. This is a consequence of the delayed setting of the correct diagnosis and, accordingly, the beginning of adequate therapy. Early detection of primary immunodeficiencies is a key factor in the successful treatment of patients with these diseases. Despite the fact that clinical warning signs were formulated more than 25 years ago, and their promotion is incredibly successful, the correct diagnosis is delayed for most immunodeficient patients by years. This situation is a consequence of an extremely wide range of clinical manifestations of immunodeficiencies. At the moment, there are several lists of warning signs. There is also an approach in which alarming clinical signs are formulated separately for different specialists. All of these lists are the result of attempts to increase the sensitivity and specificity of this instrument. These attempts each time turned out to be unsuccessful, since they slightly increased its effectiveness. The work of immunologists from Great Britain, Germany, Egypt, USA showed that it is almost impossible to formulate a list of warning signs from only clinical and anamnestic indicators. Apparently, it is necessary to add screening laboratory techniques.