In 1968, Coombs and Gell proposed a classification of allergic disorders based on then available knowledge in immunology. Four types of reactions were identified: type I , immediate (IgE-mediated); type II, cytotoxic (mediated by antibodies and Fc-receptors of cells); type III, mediated by immune complexes, and type IV, the delayed type (T-cell-mediated). This classification proved to cover pathogenesis of allergic disorders, but also the mechanisms  of autoimmune, infectious and parasitic diseases. Rapid development of immunology at the edge of XX and XXI centuries has revealed many new patterns that required updating the classification. In 2023, the European Association of Allergists and Clinical Immunologists (EAACI) proposed its own classification. It included the first 3 types from the Coombs and Gell classification. Meanwhile, the type IV cell-mediated reactions were divided into 3 subtypes: type IVa - T1 (type Th1), IVb - T2 (type Th2), IVc - T3 (type Th17). In addition, 3 more types were added: type V, with alteration of epithelial barriers; type VI, metabolically induced immune dysregulation, and type VII, with direct inflammatory response to chemicals. Unfortunately, the EAACI2023 classification does not provide a complete pattern. It does not follow a single classification principle, relying on pathogenetic, etiological, or structural aspects. But the main drawback of this classification is that the authors continue to consider allergic diseases as a separate area, while there is nothing special about them. In fact, there is no specific mechanism seen in allergic diseases that could be, at least, somehow differ from the general immunological reactions. Moreover, all these mechanisms were formed in the course of evolution as protective mechanisms, and not as pathological ones. This article concerns modern concepts of immune response, specifying 6 types of immune reactions and 5 levels of their implementation. In addition, 5 types of effector mechanisms of immune reactions are considered, forming a complex multi-level network of immune protection. The need for knowledge of immunology by clinicians of any specialty for adequate usage of immunodiagnostics and immunotherapy with bioengineered drugs is highlighted.

Morphological basis of the homeostatic immune system is made up of lymphoid and hematopoietic organs, as well as numerous clusters of lymphoid cells scattered throughout various organs and tissues of the body. According to their morpho-functional significance, they are divided into central and peripheral organs. The thymic gland is the only place where T lymphocytes are produced. In the thymus, thymocytes undergo differentiation and proliferation, eventually leading to the formation of two T cell populations. The main issue is that there is no differentiation of T cells in the thymus into T cells of effector subpopulations. This is the prerogative of the periphery. However, before becoming effector cells at the periphery, T cells migrate from the thymus and remain in circulation for a certain time without settling in secondary lymphoid organs. These cells are no longer thymocytes, but they are not yet naive T cells on the periphery, being recent thymic emigrants (NTE). Thus, they represent a separate population of T cells, one of three dominant populations of T cells. Moreover, the cells of all these three macropopulations differ from each other in a number of morphofunctional characteristics. NTE cells become the object of evaluating their quantitative and qualitative characteristics. It turned out that in many diseases with immunopathogenetic component (and, possibly, in all of them), the number of NETs decreases depending on the type of disease and its stage of development. In some cases, there is evidence of changes in percentage of Treg cells and other T cells among NETs, as well as changing ratios of CD4⁺ and CD8⁺T cells. These changes in the relative contents of different subpopulations among NETs are associated with pathogenesis of underlying disease. Thus, it seems to be a strong necessity to develop comprehensive methods of quantitative and qualitative assessment of the population of NTE cells as targets for both diagnosis and therapy of immunocompromised diseases. One may assume that such an assessment will form the diagnostic basis before clinical detection of the disease and/or aggravation of its course.

Non-specific binding of antigens is provided by the so-called pattern recognition receptors (PRR) that may be located on the cell membrane, in the cytosol, or, as soluble molecules in the blood serum. Membrane receptors include: Toll-like receptors, C-type lectin receptors, scavenger receptors. TLR, NOD-like receptors, RIG-I-like receptors, AIM-2-like receptors are located in the cytosol. Soluble receptors include pentraxins, collectins, and ficolins. After entering a microorganism to lung spaces, the non-specific defense factors and innate immunity mechanisms are primarily involved in the immune response. If non-specific recognition of pathogens is ineffective, a pneumonia focus is formed. In this regard, the role of PRR in the development of community-acquired pneumonia is quite significant. To search for literature appropriate publications, an analysis of the research databases Scopus, Web of Science, Pubmed, CyberLeninka, and RINC was conducted. The studies have demonstrated the importance of TLR4 in combating both Gram-positive and Gram-negative microorganisms. In addition, the blood levels of sCD206 lectin receptor have been considered a predictor of severe pneumonia and lethal outcomes. Increased production of a CD5-like scavenger receptor was observed in pneumonia caused by S.aureus. NOD-like receptors play an important role in defense against Acinetobacter baumannii. Pentraxins perform many functions: they exhibit opsonic properties, activate complement via the classical pathway, activate neutrophils, and regulate chemotaxis and apoptosis. In adult patients with pneumonia, elevated blood CRP levels correspond to disease severity; measurement of CRP levels helps differentiate pneumonia from other acute respiratory infections. PTX3 is a factor that can help determine the severity and prognosis of pneumonia. Mannane-binding lectin (MBL) recognizes bacterial lipopolysaccharides (LPS) in capsular layer, or cell wall of Gram-negative bacteria, lipoarabinomannans, fungal mannans, SARSCoV-2 glycoproteins, PAMP of protozoa and helminths. Ficolins interact with viral, bacterial and fungal antigens. L-ficolin recognizes pneumococcal pneumolysin, activates complement via the lectin pathway, thereby neutralizing the toxin. Thus, a critical role of innate immunity factors in pathogenesis of pneumonia is well proven but requires further research. Studying the mechanisms of disease immunopathogenesis will allow development of new prognostic models and improve the efficiency of therapy, especially in severe cases of pneumonia.

The aim of the present review was to analyze the features of B cell immune response and development of immunological memory in humans after vaccination against human papillomavirus (HPV) and during natural infection, as well as to evaluate the efficiency of various types of vaccines, vaccination regimens and factors affecting the duration of protection against human papillomavirus. The literature review includes an analysis of research papers from the databases PubMed, Embase, eLibrary, CyberLeninka and Web of Science, CNKI and MEDLINE. The search period covered publications from 2000 to 2023, with a focus on the last decade. The following keywords and their combinations were used: "HPV vaccine", "B cell memory", "memory B cells", "humoral immunity", "long-term immunity", "immunological memory", "plasma cells", "Gardasil", "Cervarix". Inclusion and exclusion criteria: The analysis included original studies (randomized controlled, cohort studies) and systematic reviews devoted to the study of the humoral immune response, dynamics of specific antibodies and populations of memory B lymphocytes after HPV vaccination in humans. The exclusion criteria were as follows: publications not in English or Russian; research focused exclusively on T cell immunity; work performed only on animal models; conference abstracts and uncensored articles. Selection procedure: The selection was carried out in two stages: (1) Relevance was assessed based on the title and annotation; (2) A full-text analysis of the articles that passed the primary filter was carried out for final verification of compliance with the inclusion criteria. The final selection included 55 publications that most fully reflect the current understanding of the role of B cells in post-vaccination immunity against HPV. Human papillomavirus is the leading cause of cervical cancer. There are three vaccines: Cervarix (bivalent), Gardasil-4 (quadrivalent) and Gardasil-9 (nonavalent), which show efficiency of >90%. Vaccination reduces the risk of developing cervical cancer and other HPV-related disorders. In 2020, WHO launched a global strategy to eliminate cervical cancer as an important public health problem. The effectiveness of HPV vaccines has been confirmed by clinical and population-based studies. The 4vHPV vaccine reduces the incidence of genital warts by 76%, and prevention of cervical cancer in young women reaches 53-57%. In Finland, vaccination showed 100% protection against HPV-associated cancer in vaccinated people compared to those who were not vaccinated. Twoand three-dose regimens provide comparable protection, and a single-dose regimen has demonstrated 89-100% efficacy in a number of studies. The optimal immune response is achieved by vaccinating children aged 9-13 years with two doses. Despite some observations showing that a single dose of HPV vaccine provides good protection against precancerous lesions, the level of antibodies after one dose is lower than after two or three vaccinations. Protection after a single dose may depend more on the response of memory B cells upon repeated contact with the antigen. However, there are no data concrning B cell response after a single dose of HPV vaccine, as well as sufficient studies of local anamnestic responses upon repeated exposure. It would be a great advance in vaccinology if a single dose of HPV vaccine proved its ability to induce protective B cell memory upon repeated contact with HPV antigens.

HLA (Human Leukocyte Antigens) genes play a key role in regulating the antitumor immune response and are characterized by significant allelic and population polymorphism. Molecules encoded by HLA genes are involved in the selection of the T cell receptor repertoire, the processing and presentation of neoantigens to T cells, and the regulation of the cytolytic activity of natural killer cells. The structural features of HLA antigens, and especially the characteristics of the antigen-binding site, determine the effectiveness of their interaction with immunocompetent cells, mediating an individual’s susceptibility or resistance to various diseases, including malignancies. Tumor cell evasion of immune control and their unlimited proliferation may result from structural or functional changes in HLA molecules, leading to blockage of neoantigen presentation to cytotoxic T lymphocytes. The causes of such changes may be mutations in the genes encoding the a-chain of HLA class I molecules, the aand b-chains of HLA class II molecules, as well as in the genes encoding the synthesis of proteins necessary for the proper assembly, transport, expression and functions of HLA molecules (for example, b2-microglobulin or the invariant chain of HLA class II molecules). Low or lost expression of HLA molecules on tumor cells also contributes to decreased immune surveillance. Another factor determining the effectiveness of antitumor surveillance is “HLA diversity.” Homozygosity of HLA genes narrows the spectrum of neoantigens that can be presented to cytotoxic T cells, weakening antitumor control. This review analyzes HLA genetic factors associated with the risk of developing a number of hematologic malignancies (acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, chronic lymphocytic leukemia, and diffuse large B cell lymphoma) in various population groups. HLA markers associated with the response to therapy and long-term prognosis of certain hematologic malignancies are identified. The results of the study of the associations between the HLA phenotype and hematologic malignancies can be used in practice as additional differential diagnostic or prognostic criteria, as well as for the formation of risk groups for developing these diseases.

Cardiovascular diseases (CVD) are the main cause of mortality in general population. Pathophysiology underlying CVD development includes inflammation, endothelial dysfunction, oxidative stress, atherosclerosis, fibrosis, dyslipidemia and thromboembolism. Endothelial dysfunction affects the balance of endothelium-dependent vasoconstriction and vasodilation by increasing cytokine levels, adhesion molecule expression, leukocyte and monocyte migration, and platelet activation. The vascular endothelial growth factor (VEGF) family is an important component of angiogenesis involved in inducing migration and proliferation of endothelial cells by modulating vascular permeability and blood clotting. The VEGF family includes 5 proteins, of which VEGF-A, VEGF-B and PlGF (placental growth factor) regulate angiogenesis, and VEGF-C and VEGF-D (c-Fos-induced growth factor, FIGF) regulate lymphangiogenesis. VEGF-A is a key factor in the angiogenesis and collateral circulation (arteriogenesis) mediated by the binding of VEGF-A to the VEGFR-1 (Flt-1) and VEGFR-2 (KDR) receptors. As a result of our search, an increased risk of coronary heart disease is expected in the case of detection of certain single oligonucleotide polymorphisms (SNPs) in VEGF-A gene, in particular: rs3025039, rs699947, rs2010963, rs1570360 and rs7667298. VEGF-D is a secreted factor that regulates lymphangiogenesis, angiogenesis, and endothelial proliferation through interaction with VEGFR2 (KDR). Some studies have demonstrated an increase in VEGF-D levels caused by rs192812042 and rs234500 polymorphisms in patients with acute and chronic coronary syndromes, thus suggesting the role of VEGF-D in the formation of CVD by involving lymphangiogenesis, as well as modulating angiogenesis. Genotyping of patients at CVD risk with identification of multiple VEGF SNPs will enable timely diagnostics of patients with initially increased risk of developing cardiovascular pathology and prescribe treatment and measures, prevent development of acute cardiovascular pathology and reduce mortality caused by CVD.

The aim of this review is to analyze the role of neutrophils and the mechanisms of “keratinocyte– neutrophil” communication involving IL-17 in the immunopathogenesis of psoriasis based on published scientific data. Psoriasis is a chronic autoimmune disease, characterized by abnormal interactions between epidermal and immune cells. Keratinocytes, when exposed to trigger factors, release alarmins, antimicrobial peptides, autoantigens, cytokines (IL-1b, IL-6, TNFa, G-CSF), chemokines (CXCL1, CXCL2, CXCL8), which promote the activation of skin dendritic cells, IL-23 production, Th17 differentiation, IL-17 secretion, and attract neutrophils to the skin. In the peripheral blood of patients with psoriasis, along with an increase in the absolute neutrophil count, there is an accumulation of activated low-density granulocytes and aged neutrophils with an increased ability to form neutrophil extracellular traps (NETs) and migrate into affected skin; the level of circulating NETs also increases. In the skin, neutrophils realize their proinflammatory potential through degranulation, the formation of IL-1a, IL-1b, IL-6, reactive oxygen species, and NETosis, during which additional externalization of autoantigens occurs. Furthermore, neutrophils “suppliers” of IL-17 to the epidermis. IL-17, via IL-17RA signaling in keratinocytes, enhances the production of neutrophil-activating antimicrobial peptides (S100A7), chemokines (CXCL8), cytokines (IL-1b, IL-6, G-CSF). These cytokines can be transferred from keratinocytes to neutrophils via exosomes and induce the expression of IL-6, IL-8, TNFa, as well as NETosis, which can lead to the release of IL-17. Through NETs, epidermal neutrophils can stimulate TLR4 expression in keratinocytes and the production of IL-36g, CXCL8, CXCL1, lipocalin-2, which enhance the activation and recruitment of new neutrophils into the skin. NETs also induce the synthesis of b-defensin-2 in keratinocytes, which reduces the likelihood of developing infections in affected skin areas. Thus, in psoriasis, the interaction keratinocytes-neutrophils with the participation of IL-17 results in the formation of a “vicious circle” of inflammation. IL-17 also promotes keratinocyte hyperproliferation and impaired differentiation, which, as shown in the zebrafish model, may be due to disruption of cytone-mediated interactions between cells of different epidermal layers. The experimental and clinical data available to date and further study of the “keratinocyte–neutrophil–IL-17” system can form the basis for the selection of new diagnostic and prognostic biomarkers and the development of new therapeutic approaches for psoriasis.

Neonatalperiodisthetimewhenchildrenareextremelyvulnerableandsusceptibletolethalinfectious complications that could be prevented due to early diagnostic procedures and adequate therapy. Problems with early clinical diagnostics determine the need for searching a marker which could help to differentiate newborn with infection from the newborn with perinatal symptoms resembling infection. Blood microbiological testing frequently gives false negative results, and newborn blood culture tests have low sensitivity. Molecular methods, especially PCR, have also moderate diagnostic accuracy, and can not replace bacteriological blood testing as a reference standard. The same problems exist with C-reactive protein and procalcitonin determination. Ideal marker’s level must quickly rise after contact with pathogen prior to clinical symptoms onset and also quickly decrease after infection healing having high sensitivity and specificity. Cytokines are one of the markers for the infectious process beginning. These molecules are among first to be synthesized after bacterial recognition by pattern-recognition receptors. Their blood plasma concentrations significantly increase during first hours after antiinfectious immune response beginning. That is why cytokines levels determination during neonatal infections may serve as significant tool for early diagnostics and adequate choice for treatment strategy. In this review we tried to summarize existing data on cytokine levels in newborns with neonatal infections and sepsis, and data on its significance in diagnostic approaches. Studies on cytokine levels in newborns are few in number, and reference concentrations are not yet determined. Cytokine family consists of hundreds of molecules, most of them are important mediators of inflammation and sepsis. However not all of them are studied for blood level changes during severe infections in neonatal period. Probably simultaneous studies of several cytokine levels and their synthesis ratio could give new informative data for early neonatal infection diagnostics improvement.

Pregnancy represents the state with particularly activated constituents of hemostasis and immune systems. Hyperactivation of platelets and monocytes may be a causative factor for pregnancy complications including preeclampsia. The pathogenetic role of platelet-monocyte complexes (PMC), recognized as diagnostic marker and therapeutic target, is poorly investigated. The aim of the study was to determine quantitative changes in the peripheral blood PMC level and antigenic phenotype in preeclampsia, and to evaluate effects of platelets on the expression of monocyte surface marker proteins in normal and pathological pregnancy. The tested groups included third trimester pregnant women diagnosed with severe preeclampsia (35-41 weeks of gestation) and women with uncomplicated (physiological) pregnancies (33-41 weeks of gestation). All participants were between the age of 24 and 42 years. PMC levels and CD62P, CD11b, CD86, CD162, HLA-DR, TREM-1 expressed by PMC and free circulating cells were determined by flow cytometry in the peripheral blood total monocytes and monocyte subpopulations.It was found that PMC level increased (29.2% of total monocyte population) when compared to uncomplicated pregnancy (17.5%), and this augmentation was ensured by two PMC-forming monocyte subpopulations: classical and intermediate. Moreover, expression levels of platelet and monocyte activation markers CD62P, CD162, HLA-DR, CD86, TREM-1, CD11b were significantly higher in preeclampsia. The fractions of classical, intermediate and non-classical monocytes differently contributed to preeclampsia-associated changes in the expression levels of monocyte activation markers. Comparison of PMC and free circulating monocytes demonstrated that observed changes in the surface antigenic phenotype of monocytes within PMC were ensured by platelets and other factors. In preeclampsia, platelet-induced augmentation of monocyte inflammatory and adhesive capacities displayed itself in the increased TREM-1 and CD11b expression. In contrast, increased levels of HLA-DR and CD86 in monocytes were not induced by the interaction with platelets. The results of the study suggest that preeclampsia is accompanied by increased peripheral blood PMC levels and activation of monocytes within PMC, demonstrate immunomodulatory effect of platelets, and provide a rationale for the evaluation of expression patterns of PMC surface antigenic markers with diagnostic and therapeutic purposes.

An increased content of platelet-leukocyte aggregates suggests an elevated thrombogenic and inflammatory activity of peripheral blood cells. The aim of this study was to investigate the ratios and properties of platelet-monocyte and platelet-lymphocyte aggregates in patients with coronary atherosclerosis. The study included 19 patients with coronary artery disease and coronary atherosclerosis (15 men; 4 women; their mean age was 59.0 (55.0; 69.0) years old. The comparison group consisted of eight patients at high cardiovascular risk without coronary atherosclerosis. The atherosclerosis severity was assessed by coronary angiography and Gensini Score of ≥ 42.5 points. Platelet-leukocyte aggregates were analyzed by imaging flow cytometry. We assessed the percentage of platelet-monocyte and platelet-lymphocyte aggregates; the percentage of P-selectin (CD62P)⁺ aggregates; the number of platelets aggregated with each individual leukocyte (either monocyte or lymphocyte). In patients with coronary atherosclerosis, a significantly lower number of monocytes formed small aggregates of 1 monocyte and 1 platelet as compared to patients without atherosclerosis (Gensini Score > 0), i.e., 78.8% (68.1; 86.2) versus 84.7% (83.8; 87.1) (p = 0.039). At the same time, in patients with more severe atherosclerosis (Gensini Score ≥ 42.5), the percentage of lymphocyte aggregates with more than 3 platelets tended to increase to 0.6% (0.3; 1.6) compared to patients with Gensini Score < 42.5 with 0.1% (0; 0.8) (p = 0.075). The proportion of large platelet-lymphocyte aggregates (with 3 or more platelets) directly correlated with Gensini Score, IL-1b concentration, systemic inflammatory indices, as well as with ratios of triglycerides/glucose and triglycerides/high-density lipoprotein cholesterol (insulin resistance indices), and showed inverse correlation with high-density lipoprotein cholesterol concentration. The percentage of small aggregates (1 lymphocyte with 1 platelet) inversely correlated with severity of coronary atherosclerosis, IL-1b concentration, and insulin resistance index. Thus, the larger size of heterotypic aggregates but not the increased number of platelet-leukocyte aggregates seems to be a distinguishing feature between patients with coronary atherosclerosis. Formation of large aggregates with 3 or more platelets is an unfavorable sign which is also associated with intensity of systemic inflammation and metabolic imbalance.

VEGF-A is significant cytokine associated with angiogenesis. In SARS-CoV-2 infection (COVID-19), an increased level of VEGF-A was detected in serum being associated with severity and mortality of the disease. A number of polymorphic sites have been identified in regulatory regions of this gene that are associated with VEGF production. The VEGF-2758 (rs699947) is located in promoter region of this gene and the VEGF-2578 CC genotype is associated with higher production rates. The VEGF 936 (rs3025039) is located at the 3' untranslated region of VEGF gene, and its T allele is associated with a reduced plasma protein level. The aim of the study was to analyze the association of polymorphic positions of the regulatory regions of the VEGF gene (rs699947 and rs3025039) with clinical severity of the disease and cardiovascular problems in patients from the West Siberian region of Russia who previously suffered with COVID-19. The study included 260 former COVID-19 patients with varying degrees of severity. The examination took into account the previous history of cardiovascular diseases (CVD) and those with first clinical CVD signs occuring after the infection. VEGF rs699947 and VEGF rs3025039 were genotyped using TagMan probes. The significance of distribution differences in the studied genetic features was determined using a two-way version of the exact Fisher test. We did not find any differences in distribution of the genotype frequencies, both for single polymorphic positions and the complex VEGF-2578/VEGF+936 between the groups with varying degrees of the disease severity (severe, moderate, and mild), both in general group of patients, and in the subgroup of patients with CVD history. Moreover, there were no significant differences revealed between patients with newly emerged CVD after infection compared to patients without similar complications, both for single genotypes and in VEGF-2578/VEGF+936 complexes. According to our data, the functional polymorphism of the VEGF gene at these gene locuses is not associated with either COVID-19 severity, or with cardiovascular disorders accompanying the disease. Changes in VEGF levels may be due to various factors affecting it, thus requiring additional studies.

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by a high risk of vascular complications causing disability and mortality. Immune system dysfunction, especially, imbalance of regulatory T cells (Tregs), plays a central role in pathogenesis of T1DM. Interleukin-2 (IL-2) is a key cytokine for maintaining the Treg function. The T330G (rs2069762) polymorphism in promoter region of IL2 gene may affect its production, but its association with pathological biomarkers of diabetes is not well understood. Our aim was to investigate the possible association between T330G polymorphism of IL2 gene and the levels of laboratory markers reflecting systemic inflammation, endothelial dysfunction, fibrogenesis, and intestinal barrier permeability in T1DM patients. This cross-sectional study included 90 patients with T1DM. Genotyping for the IL-2 T330G polymorphism was performed using PCR method. Plasma concentrations of angiotensin-2, transforming growth factor-b (TGF-b), endothelin-1, C-reactive protein (CRP), markers of intestinal permeability (zonulin, LBP, BPI, sCD14), and other protein factors were determined by ELISA technique. Statistical analysis was performed using non-parametric methods. It was found that the carriers of TT genotype associated with lower IL-2 production, had statistically significantly higher levels of angiotensin-2 compared to the subjects with GG genotype (median 192.4 pg/mL vs. 88.0 pg/mL; p = 0.021). Patients with the TT genotype also showed higher concentrations of TGF-b compared to the heterozygous TG group (median 2.7 ng/mL vs. 1.8 ng/mL; p = 0.015). No significant associations of T330G polymorphism were found with levels of CRP, markers of intestinal permeability, or clinical parameters, including HbA1c and the frequency of The T330G polymorphism of IL2 gene in patients with T1DM is associated with activity of renin-angiotensin system and the levels of TGF-b, the main profibrotic cytokine. The genetically determined decrease in IL-2 production (TT variant of T330G polymorphism) may contribute to hyperactivation of these systems, thus playing a key role in development of vascular complications. This gene variant could be considered a potential genetic marker for risk stratification and personalized therapy in T1DM.

Pterygium is a fibrous neoplasm of the conjunctiva, which may have different pathomorphological characteristics depending on the region of residence. It is necessary to take into account regional factors that serve as local predictors of the risk of occurrence, course of the disease and relapse of the disease. Risk factors include insolation, harmful working conditions, climatic conditions. The purpose of the study was to study the morphological features of pterygium, determine the spectrum of cytokines and growth factors in biopsy tissues of patients with pterygium in the Southern Urals. A total of 68 eyes with a diagnosis of primary pterygium were operated for the period 2005 to 2025. Patients of both sexes aged 41 to 80 years. Morphological (hematoxylin and van Gieson staining) and immunohistochemical (FGF-b, Nf-h, PCNA, TGF-b, MMP-9, Timp-2, c-kit, Pro-col3, Col 1, HLA-DR, CD206, TNFa, VEGF-R, p-53) studies of biopsy specimens were performed. Statistical analysis of cell counts was performed using nonparametric methods in Statistica 10.0 software. It was found that the ratio of the fibrous component to the vascular-cellular component varied. In some tissues of the primary pterygium, signs of active collagenogenesis were detected, while in others, active proliferative activity was observed. Thus, in some pterygium tissues, the ratio of stromal elements to the vascular-cellular component shifted towards the latter. The stroma contained a large number of blood and lymphatic vessels with dilated lumens, intense tissue infiltration by stromal (fibroblastic) and inflammatory (macrophages, leukocytes, lymphocytes) cells, thin bundles of collagen fibers with a large amount of amorphous substance. Morphologically, pterygia were divided into three types: proliferative, fibromatous and atrophic-sclerotic. The proliferative group of pterygia contained more M2 macrophages of the CD206 phenotype, mesenchymal stem cells c-kit, MMP-9⁺ and VEGF-R⁺ cells than in fibromatous and atrophic-sclerotic types. Expression of FGF-b, HLA-DR, p-53 by cells was observed in all types of pterygium to the same equal extent. In proliferative pterygium, the amount of mature collagen type 1 exceeded the quantitative values of fibromatous and atrophic-sclerotic types. And the amount of immature reticular collagen type III and profibrogenic growth factor TGF-b in cells, on the contrary, significantly statistically significantly increased as tissue fibrosis progressed. Therefore, it is necessary to level or correct immunodeficiency, eliminate autoimmune complexes, reprofile macrophages from growthstimulating M2 to proinflammatory M1, stimulate TIMP-2, and inhibit conjunctival vasculogenesis.

Recent epidemiological studies show a rising prevalence of allergic rhinitis (AR) in children. Early identification of symptoms, sensitization patterns, and causative respiratory allergens enables timely allergenspecific immunotherapy, which may prevent asthma development. The present study aimed to characterize disease features, risk factors, sensitization profiles, and clinically relevant allergens in young children with AR living in Magnitogorsk. An open-label, single-center, prospective study included 92 children with AR (aged 2-4 years, mean 3.15±0.80) and 45 age-matched controls. All participants (n = 137) underwent clinical (blood counts, urinalysis), biochemical, parasitological, and allergological testing (sIgE, ImmunoCAP). Children with AR and polyvalent sensitization (n = 11) were further evaluated using ISAC-112. AR symptom onset occurred at a median of 29.00 (24.00-36.00) months (range: 8.00-45.00). Persistent AR was observed in 77.2% of patients, while 22.8% had intermittent symptoms. Moderate-to-severe AR (37% of cases) had the severity scores of 7.00 (6.00-8.00) (by a visual analogue scale). Significant AR risk factors included: family history of atopy (OR 4.4; 95% CI 2.2-8.9); parental history of persistent AR (OR 10.4; 95% CI 2.4-44.4); comorbid allergies (OR 17.1; 95% CI 6.4-45.9); history of wheezing (OR 10.8; 95% CI 3.7-31.5); atopic dermatitis (OR 3.9; 95% CI 1.4-10.3); cesarean delivery (OR 2.8; 95% CI 1.2-6.8); pet exposure (OR 3.6; 95% CI 1.8-7.3); and parental smoking (OR 2.8; 95% CI 1.4-5.8). Cat dander (71.74%), dog dander (70.65%), and birch pollen (67.39%) were the most frequent sensitizing allergens for the studied group in Magnitogorsk. Seasonal AR symptoms were revealed in 57% of patients, while 35.44% reacted to animal allergens. Sensitization to major allergens Bet v1 (birch) and Fel d1 (cat) did confirm the true allergic responses. A complete symptom control and prevention of bronchial asthma are the primary treatment goals for children with AR. Early diagnosis and precise treatment strategies are essential to meet these objectives.

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by impaired epidermal barrier function, immune dysregulation, and altered microbial ecology. Over recent decades, there has been a steady increase in its prevalence, making AD one of the most pressing issues in dermatology. The aim of this study was to comprehensively assess bacterial skin colonization in patients with AD using real-time quantitative PCR and to analyze its relationship with clinical and immunological parameters of the disease. A prospective study included 110 patients with AD and 86 apparently healthy individuals. The disease severity was assessed using the SCORAD index; total IgE levels and complete blood count were measured, and quantification of skin microbiota was performed by real-time PCR. The results revealed a significant increase in bacterial load in the AD group compared to controls: total bacterial mass was 32 times higher, while Staphylococcus spp. and Staphylococcus aureus were 100 times higher. The concentration of Streptococcus spp. did not differ significantly. A strong positive correlation was found between the SCORAD index, total IgE level, absolute eosinophil count, and the quantity of total bacterial mass, Staphylococcus spp., and S. aureus, whereas a weak negative correlation was observed for Streptococcus spp. Patients with severe AD had significantly higher IgE levels. The obtained data confirm the central role of S. aureus and microbial dysbiosis in AD pathogenesis. The established threshold values of bacterial load (total bacterial mass > 5.0 log copies/mL, S. aureus > 4.0 log copies/mL) may serve as objective criteria for prescribing targeted antimicrobial therapy.

High prevalence of HIV/HCV coinfection among injection drug users (IDUs) in the Republic of Tatarstan requires studies on the influence of behavioral factors on immunopathology. Objective of our study was to conduct a comparative analysis of immunological parameters in IDUs with HIV/HCV coinfection and those without a history of drug use. This single-center comparative study included 38 patients with HIV/HCV coinfection who used injection drugs and 36 patients with HIV/HCV without a history of drug use. The sample size was calculated to achieve 80% power at a significance level of p < 0.05. Lymphocyte subpopulation profiles and circulating immune complex levels were assessed. In the IDU group, a more pronounced decrease in the level of CD4-lymphocytes (26.2±0.7% vs 30.1±0.8%; p < 0.001) and the absolute number of CD4⁺ cells (0.43±0.04 vs 0.61±0.04×10⁹/L, p < 0.01) was revealed. The immunoregulatory index was significantly lower in the IDU group (0.60±0.02 vs. 0.75±0.02, p < 0.001). The level of circulating immune complexes (CIC) was significantly higher in the IDU group (568.3±30.5 vs 402.3±28.0 arb.units, p < 0.001). In cases with clinical stage III of HIV infection, IDUs demonstrated the greatest reduction in absolute lymphocyte count (24.1±0.9% vs. 31.3±1.6% in stage II patients, p < 0.001). The injection drug usage is an independent factor exacerbating immune dysfunction in HIV/HCV co-infection. These findings support the need to develop differentiated approaches to monitoring and management of this cohort.

The study involved 73 patients aged 5-15 years of Russian origin upon hospital admission for surgical treatment of congenital obstructive uropathies (hydronephrosis, vesicoureteral reflux, megaureter). All patients underwent a full range of standard urological examinations, including urine cultures for microflora with an antibiotic resistance testing and microbial counts. Microbiological analysis of uropathogenic bacteria has revealed that Staphylococcus aureus (45.0%) and Staphylococcus epidermidis (22.5%) were most often cultured from the urine of patients. The children with secondary pyelonephritis underwent genotyping for the HLA-A and HLA-B loci. Statistical methods: canonical correspondence analysis, calculation of relative risk and odds ratio. The aim of our study was a search for relationships between the HLA Class 1 antigens of MHC complex (loci A and B of the HLA system), and positive findings of S. aureus and S. epidermidis in children with obstructive pyelonephritis. Results: We used the Past program (version 3.26, 2019) , with S. aureus and S. epidermidis taken as independent variables causing pyelonephritis in children, and histocompatibility antigens of loci A and B (dependent variables).  The combined relationships were revealed between HLA (A and B loci), being associated with detection of S. aureus and S. epidermidis in children with secondary pyelonephritis. The odd ratios for S. aureus were as follows: A28 (42.8), A27 (10.4), A11 (10.4), A26 (5.0), B28 (12.7), B15 (5.0), B1 (4.33). For S. epidermidis: A4 (6.7), A25 (4.9), B 41 (6.7), B16 (4.9). With, the highest significant relative risk for detecting S. aureus was revealed among pediatric patients with pyelonephritis who have HLA - A28 antigen, with relative risk of 24.5 (P=0.028), and odds ratio of 42.78 (P= 0.019). Conclusions: The obtained data may be used to predict the risk and clinical course of pyelonephritis, as well as to guide the strategy of etiotropic therapy of obstructive pyelonephritis in children.

Diagnosis of kidney cancer presents significant difficulties, since symptoms of the disease may appear only at an advanced stage. Special attention is paid to the search for biomarkers that allow for rapid and effective tumor diagnosis and disease prognosis, including detection of mRNAs expressed by genes regulating the immune response. The aim of present study was to evaluate expression of CD16A, CD16B, ICAM1, CD38, FoxP3 mRNAs in tumor samples of the patients with clear cell renal cell carcinoma. The study included 400 patients aged 45-68 years with histologically confirmed clear cell renal cell carcinoma, mainly at stage I-II (73%, 292/400), grade 2 (57.3% of observations, 229/400). Most patients underwent radical nephrectomy (279/400, 69.8%). All patients have signed an informed consent before the study. Tumor tissue samples (3 mm3) were collected on the day of surgery. The mRNA was obtained from tumor samples, and detected by real-time reverse transcription-PCR technique, being calculated in arbitrary units. The ubiquitin ligase C (UBC) gene was used as a housekeeping gene and positive control. Statistical processing of the results was performed using Statistica v.10.0 and MS Excel 2010. The most frequently expressed mRNAs in the tumor tissue were as follows: CD16A (100%); CD38 mRNA (93.3%, 280/300); CD16B mRNA (92%, 276/300), and the least frequently detected mRNA was FoxP3 (56%, 168/300). The detection rate of ICAM1 mRNA was 84.7% (254/300). The revealed differences in mRNA detection still persisted when comparing expression of distinct mRNAs in patients with different size of primary lesion, according to the TNM classification, different stages of the disease, its prognosis, degree of tumor malignancy and different outcomes of the disease. The frequency of FoxP3 mRNA detection was increased in patients with stage IV tumors, but it remained lower than the frequency of CD16A, CD16B, ICAM1, CD38 mRNA detection. In malignant tissues of patients with clear cell renal cell carcinoma, we have found a highly frequent detection of mRNAs for CD16A, CD16B, CD38, along with low expression of FoxP3 mRNA, regardless of nunerous clinical and morphological predictors of the disease prognosis.

Diphtheria is a serious infection, often characterized by a pronounced toxic component, which can be accompanied by severe complications of the cardiovascular and nervous systems. The primary method of infection prevention is immunization (primarily in children) with diphtheria toxoid, which induces effective and long-lasting antitoxic immunity. Objective of the study: evaluation of collective immunity to the causative agent of diphtheria among the population of several regions (Amur, Irkutsk, Nizhny Novgorod, Kaliningrad) and the Republic of Crimea. Materials and methods. The cross-sectional cohort randomized study involved 18,207 people uniformly stratified by age (1–5, 6–11, 12–17, 18–29, 30–39, 40–49, 50–59, 60–69, 70+ years), including: 3,576 in Amur; 3,657 in Irkutsk; 3,580 in Nizhny Novgorod; 3,613 in Kaliningrad regions; and 3,781 in the Republic of Crimea. All studies were conducted in strict accordance with the requirements of the Declaration of Helsinki. Immunoglobulin G Abs to the C. diphtheriae toxin were determined in the examined volunteers by enzyme immunoassay using a Russian-made test system. Data analysis and statistical processing were carried out using a web application. Results. The average cohort regional seroprevalence levels were: Amur Region - 82.3% (95% CI: 81.0 - 83.5); Irkutsk - 87.6% (95% CI: 87.6-88.9); Nizhny Novgorod - 86.5% (85.3-87.6); Kaliningrad - 74.2% (95% CI: 72.8 - 75.6); and the Republic of Crimea - 74.8% (95% CI: 73.4-76.1). In some cases, seropositivity did not reach 60%, namely: among individuals aged ≥60 in the Kaliningrad Region and the Republic of Crimea; and among individuals aged ≥70 in the Amur and Nizhny Novgorod Regions. Most volunteers had serum IgG Abs to diphtheria toxin at concentrations of 0.1–1.0 IU/ml, regardless of age, region, or vaccine type. Conclusion. The level of collective immunity mandated by current Russian documents (95% in children, 90% in adults) was practically not achieved in any region or age group (except children aged 1–5 years in the Irkutsk and Nizhny Novgorod Regions). In all regions, the least protected group were individuals aged 60 and older, among whom the seronegative value reached 30–45%.

NK cells represent the predominant endometrial lymphocyte subpopulation. During implantation phase, NK cells participate in communications with embryo, thus influencing successful implantation. However, there is currently a lack of literature data regarding potential influence of pre-implantation embryos on functional activity of NK cells. The role of NK cells in the utero-placental contact zone is to control trophoblast invasion, stimulate or limit it. Cytokines secreted by both embryo and NK cells, e.g., IL-1b, IL-6, IL-8, GM-CSF, and IP-10, have been shown to stimulate migration and invasion of trophoblast cells Therefore, the purpose of this study was to develop a cellular diagnostic technology for predicting reproductive failure by investigating the effect of the spent, embryo-conditioned culture media (ECM) on the cytotoxic activity of NK cells towards trophoblast JEG-3 cells using an in vitro cytotoxicity model. We have found that the death rate of Jeg-3 cells after co-culture with NK-92 cells was higher than the rates of spontaneous Jeg-3 cell death. In general, the series of spent ECM, which were not divided into groups by quality of the cultured embryos, have reduced the death of Jeg-3 cells when co-cultured with NK-92 cells. We have revealed that ECM from grade A (excellent-quality) embryos reduce the effector functions of natural killer cells against JEG-3 trophoblast cells. Hence, we suggest that the embryos with highest implantation potential (grade A) secrete factors that suppress NK cell cytotoxicity toward trophoblast cells, thereby promoting embryonic survival and its successful implantation. Previously, we have detected cytokines affecting NK cell functions IL-6, IL-8, IL-1b, IL-10, IP-10 and GM-CSF secreted by excellent quality embryos into a spent culture medium. Thus, excellent-quality embryos with the greatest implantation potential secrete factors that modulate NK cell effector functions at the maternal-fetal interface. The method of assessing the embryo quality by means of functional model is, generally, consistent with morphological approach to the quality assessment of embryos and may be recommended for usage in clinical practice.

Mesenchymal stem cells (MSC) are considered a promising tool for cell therapy due to their regenerative and immunomodulatory properties. However, results from clinical trials remain inconclusive: clinical improvements have been shown in some studies, while other trials did not reveal statistically significant differences from placebo-treated patients. Moreover, some participants experienced adverse effects. Targeted preconditioning of the cells aimed for modifying of their secretome seems to be a strategy to improve the safety and efficacy of MSC-based therapies. Another promising approach is modulation of mitophagy, a key mitochondrial quality-control mechanism that determines stress resilience and immunoregulatory capacity of MSCs. Active mitophagy reduces senescence and preserves immunomodulatory functions of MSCs, thus promoting resolution of inflammation. When mitophagy is impaired, the mitochondrial components and reactive oxygen species may accumulate, thus exacerbating local inflammation. As a result, the therapeutic potential of mesenchymal stem cells may be diminished. Thus, the aim of this study was to compare mitophagy and inflammatory tolerance of MSCs under different stimulation regimens. In the present study, we compared both strategies by examining the mitophagic response of mesenchymal stem cells to mitochondrial stress and the development of LPS-induced tolerance. We used the hTERT-immortalized adipose-derived line ASC52telo in two complementary experimental schedules. To probe mitophagy process, the cells were exposed to FCCP to depolarize mitochondria and then subjected to confocal microscopy after dual staining of mitochondria and lysosomes. To assess their tolerance, the cells were stimulated twice with LPS, and cytokine secretion was measured. We found that FCCP induced pronounced mitochondrial fragmentation and activation of mitophagy. In a separate set of experiments, repeated LPS stimulation led to a marked reduction in TNF and CCL2 secretion. Thus, activation of mitophagy in response to acute mitochondrial stress and establishment of endotoxin (LPS) tolerance in mesenchymal stem cells may be regarded as complementary adaptive mechanisms. These processes may be exploited as targets to increase the predictability and clinical efficacy of MSC-based therapies.

Post-COVID syndrome, known as long COVID, is characterized by prolonged systemic inflammation and vascular dysfunction, particularly in individuals with arterial hypertension. MicroRNAs, such as miR-155 and miR-28, are regarded as potential molecular markers of this pathological condition. This study aimed to evaluate the expression patterns of miR-155 and miR-28 in patients with long COVID depending on the presence of hypertension, and to evaluate their associations with markers of inflammation and vascular impairment. A total of 102 patients were examined at least four weeks after recovery from COVID-19. Two groups of patients were formed, i.e., individuals with or without arterial hypertension (respectively, 50 and 52 subjects). Plasma levels of miR-155 and miR-28 were measured using reverse transcription quantitative PCR. General statistical and correlation analyses were performed. The results demonstrated that patients with hypertension exhibited elevated expression of miR-155 and reduced levels of miR-28, along with increased concentrations of inflammatory markers such as C-reactive protein, interleukin-6, B-type natriuretic peptide, and fibrin degradation products. In contrast, normotensive patients showed more stable biomarker profiles. These findings suggest that miR-155 and miR-28 reflect the degree of inflammatory and vascular activation in long COVID. The association between hypertension and dysregulation of these microRNAs highlights their potential utility for risk stratification and post-infection monitoring in affected individuals.

Long-term sequelae of COVID-19 include disturbances in the immune and endocrine systems. Of particular interest is the role of cortisol as a key stress response hormone, potentially affecting restoration of immune homeostasis in patients with post-COVID syndrome. Altered regulation of the hypothalamic-pituitary-adrenal axis may form various immune phenotypes that complicate individual adaptation after infection. Our objective was to assess the parameters of immune response in patients with post-COVID syndrome depending on the blood cortisol level, emphasizing the indices on natural killers, T-lymphocytes and platelets. Materials and methods: We have examined 109 patients who had COVID-19 at least 6 months ago. Blood serum samples were collected in the morning time. Serum cortisol levels were measured in order to stratify patients into three groups: with normal, elevated and reduced values. Immune status of the patients was assessed by flow cytometry. The levels of NK cells, T lymphocytes and their subpopulations (helpers, cytotoxic cells) were analyzed both by CD45+ and CD46+ panleukocyte markers, as well as general blood test parameters, including the mean platelet volume. Statistical evaluation was performed by means of nonparametric methods. Results: Patients with low cortisol levels showed a significant reduction in both absolute and relative number of NK cells, as well as a decrease in the average platelet volume. In this group, an increased number of T lymphocytes was also observed. In patients with hypercortisolemia, a decreased level of T cytotoxic cells was recorded. The immune differences clearly correlated with individual cortisol levels. Conclusions: The obtained data demonstrate presence of at least two immune phenotypes in post-COVID patients: (1) a pattern associated with hypercortisolemia and decreased cytotoxic T cells; (2) phenotype with hypocortisolemia, NK cell deficiency and platelet activity. These differences suggest a need for taking the hormonal status into account when assessing and treating post-COVID conditions.