Vol 28, No 2 (2025)

Cell therapy is among the main methodological approaches in regenerative medicine. Its effectiveness is determined by the use of cell cultures containing the largest available number of viable cells. An important role in this process is played by growth factors that ensure cell proliferation and differentiation. Both recombinant proteins and native proteins from various biological fluids may be used as growth factors. Blood platelets, being anucleate cells, are a promising source of growth factors. Along with their main blood clotting function, the platelets contain a number of unique biological molecules in alpha granules, i.e., mediators involved in immune response, inflammation and regeneration processes. The major families of growth factors present in platelets are: platelet-derived growth factors (PDGF), transforming growth factors (TGF-β), vascular endothelial growth factors (VEGF), epithelial growth factors (EGF), fibroblast growth factors (FGF), insulin-like growth factors (IGFs). The PDGF family includes several subtypes: PDGF-AA, PDGF-BB, PDGF-AB, PDGF-CC, PDGF-DD. PDGF-BB has high angiogenic, chemotactic and mitogenic activity. It takes part in the proliferation and migration of interstitial cells in various organs, proliferation of smooth muscle cells in respiratory tract, development of cerebral vessels and renal glomeruli. The aim of our study was to examine the content of PDGF-BB factor in platelet lysates obtained from healthy donors. Platelet lysate is a complex cocktail containing many growth factors, cytokines, and chemokines. The concentration of specific factors in final product obtained from platelet concentrate is different for each donor, and, apparently, depends on age, gender, blood type and other individual differences. When choosing a growth additive for a cell culture, the cell biologist should be focused on high content of the trophic factor that most closely matches the goals of the given experiment. The use of recombinant additives in the culture medium is justified by precise dosage of these components. However, the use of natural sources may be more preferable, due to presence of different growth factors required for in vitro expansion of highly cellular viable cultures. According to our results, the optimal additive for obtaining viable fibroblasts, endothelial cells, mesenchymal multipotent stem cells is a growth-inducing product obtained from platelet lysate of female donors of Bα (III) group, and male donors of Aβ (II) blood groups which contain the highest concentration of PDGF-BB.

Until recently, the studies of pathogenetic mechanisms of different diseases were focused on evaluation of the major cell populations, changes in their quantitative and qualitative characteristics, such as gene expression profile, secreted factors, surface markers, etc. Nowadays, the minor cell subpopulations, their low amounts in peripheral blood are of considerable interest. These cells may function in variable ways, by polarizing the immune response, or participating in regulation of the immune reactions. One of such minor subpopulations is presented by CD4⁺CD8⁺ double-positive T lymphocytes which comprise up to 3%, of blood lymphocyte contents. However, these cells are a predominant subpopulation among all T cells in thymus (about 75%). Peripheral double-positive T lymphocytes are a special subpopulation of T cells, because they have no markers characteristic of immature T cells of the thymus, but they bear memory cells antigens, e.g., the CD1a molecule, and a reduced amount of TREC, thus indicating a differentiated mature phenotype. At the same time, these cells may have different phenotypes and functions performed by them. However, the role of CD4⁺CD8⁺ double-positive T lymphocytes have not been well studied. There are positive correlations between an increase in double-positive T lymphocytes and demographic and anthropomorphological characteristics, such as age, gender, body mass index. It is known that the contents of this cell subpopulation increase in various pathological conditions, for example, in mononucleosis caused by the Epstein-Barr virus, cytomegalovirus, human immunodeficiency virus, hepatitis C, hemorrhagic fever virus, like as in oncological, autoimmune and allergic diseases. Thus, the peripheral CD4⁺CD8⁺T cells are assumed to play an important role in regulating immune responses under pathological conditions. We assessed the relative number of CD4⁺CD8⁺ double-positive T lymphocytes in immunodeficiencies in different groups depending on age, gender, and certain diagnostic markers, i.e., detection of Staphylococcus aureus, vitamin D deficiency, intestinal or mixed giardiasis, a positive PCR result for a viral infection, and the status of a COVID-19 reconvalescence. We obtained a statistically significant increase of of CD4⁺CD8⁺T cell numbers in both men and women, and the number of cells was also changed depending on age, but the selected criteria did not reflect the numerical changes of these cells. A more detailed study on the role of double-positive T lymphocyte subpopulations is necessary, both in immune disorders, and under normal health conditions, because CD4⁺CD8⁺ double-positive T lymphocytes can be a significant tool of immune response regulation and sustainability of immunity.

The aim of the present study was to specify changes in immunoglobulin E (IgE) in patients with chronic dermatoses (psoriasis and vitiligo). The study involved 168 patients with psoriasis and vitiligo, aged 18 to 65 years, undergoing treatment at the Karakalpak branch of the Republican Specialized Scientific and Practical Center for Dermatovenereology and Cosmetology. IgE levels were determined by means of enzyme-linked immunosorbent assay method (“Vector Best”, Russian Federation). Analysis of the results has revealed an increase in IgE levels in a certain number of patients with different clinical forms of psoriasis. It was established that the IgE level was higher during the progressive stage (191.8 ± 42.95 IU/mL), being 16-fold higher than the values in control group. At the stationary stage, the IgE level in the serum was 10 times higher than the control values, averaging 116.72 ± 20.55 IU/mL. Hences, our studies have shown that the patients with psoriasis living in the Aral region exhibit a significant increase in IgE concentration in blood serum (13 to19-fold over controls). The highest increase in serum IgE was found in patients with erythroderma (19 times over normal range). Analysis of IgE levels in vitiligo revealed an increase in a smaller subgroup of patients. Analysis of patients with elevated IgE levels in vitiligo has shown that these patients had concomitant allergic conditions, i.e., allergic rhinitis and atopic dermatitis. The conducted studies confirm the severity of changes in immune system parameters, including compensatory and reagin-mediated mechanisms, along with activation of cellular autoimmune processes in patients with dermatoses, which vary in intensity depending on clinical severity of the condition. When analysing the changes in IgE levels depending on clinical form of psoriasis, an increase in IgE levels was found in all clinical forms of psoriasis. The highest increase in serum IgE was observed in patients with erythroderma (230 ± 76.91 IU/ mL), which is 19 times higher than in practically healthy individuals. In psoriatic arthropathy (185 ± 44.36 IU/mL) and onychodystrophy (178.33 ± 43.43 IU/mL), it was 15 times higher. In the patients with psoriasis vulgaris, IgE level was 13 times higher (157.77 ± 34.61 IU/mL), and in the palmoplantar form 8 times higher than in controls (95.4 ± 23.05 IU/mL). Upon study of IgE levels in vitiligo, an increase was found in 27% of the total group, whereas 63% showed normal IgE levels. Analysis in the patients with elevated IgE levels revealed that these patients had concomitant allergic pathology manifesting with allergic rhinitis and atopic dermatitis. The patient with the highest IgE level had a family history of psoriasis, i.e., his father had psoriasis.

Allergopathology is a multifactorial group of diseases that includes clinical manifestations from the skin, gastrointestinal and respiratory systems. This group of diseases is based on the mechanisms of hypersensitivity types I, V and VI. These disorders can manifest with similar clinical features. In addition, they must be differentiated from infectious syndrome of primary immunodeficiencies, with onset of an autoimmune disorder, rhinopathy associated with endocrine diseases, enzymopathies. The cohort of children with allergic rhinitis is heterogeneous, due to potentially variable course of hypersensitivity and combination of various pathogenetic pathways. The aim of our study was to develop a personalized approach to diagnosis and therapy in children with manifestations of rhinitis and prolonged cough syndrome. The study included a group of 53 children aged 2 to 18 years who consulted an allergist-immunologist with leading complaints for nasal congestion and prolonged cough. We also excluded infectious factors of hypersensitivity. According to the results of examination and anamnesis, rhinitis was combined with postnasal drip in all patients (n = 53, 100%); episodes of broncho-obstruction and laryngospasm were observed in 20 patients (24%), bronchial asthma attacks – in 7 children (13.2%). Polyresistant bacterial microflora was detected in 20 patients. Allergosensitivity was revealed in 31 children. Rhinopathy associated with alactasia was found in 8 children, with hypolactasia against the background of regular consumption of dairy products – in 5 children. Sanation of chronic flora and dietary therapy was followed by remission of rhinopathy. In 7 patients, the iron deficiency conditions led to sensitivity to bacterial flora. In the structure of sensitization, allergens of house dust mites predominated (61.3%), along with food sensitization (48.4%), epidermal allergens of animals (45.2%), plant allergens (54.67%). In the cases where we identified diagnostically significant allergens, allergen-specific immunotherapy with sublingual (SLIT) drugs was recommended to children. During the year of observation, 12 subjects underwent treatment with house dust allergens; 5, with birch allergens; 3, with a mixture of meadow grass allergens, and one child with wormwood. Some patients still needed pharmacotherapy. After the first course of SLIT, all patients experienced a significant relief of the syndrome. Thus, personalized diagnostics should include a thorough examination: allergy diagnostics, exclusion of gastrointestinal pathology and enzymopathies, detection and sanitation of chronic foci of infections, including parasitic invasions. Such an algorithm may significantly alleviate the severity and duration of clinical manifestations of rhinopathy.

Allergy mapping is a modern technique for diagnosing allergic diseases in immunocompromised patients. Frequent recurrent respiratory viral infections lead to altered classic course in allergic diseases. The aim of the study was to assess the prevalence and spectrum of sensitization in immunocompromised patients and patients with helminthiasis in the Republic of Ingushetia. Allergological examination of patients included prick tests, a blood test for specific IgE using ImmunoCAP. This study was conducted to study the prevalence and type of sensitization in 30 immunocompromised patients aged 18 to 55 years suffering from AR, AtD, PA. Of them, 23 subjects (77%) suffered from allergies and chronic viral infections (CMV, EBV, type 6 HHV, type 1 HSV), with frequent acute respiratory infections, 7 patients (23%) suffered from allergies and parasitic invasions. Food allergies were detected in 7 cases. In these patients, sensitization to Bos d 4 was detected in 57%; to Gal d 1.5, in 43%; to Tri a 14, in 43%; to Mus a, 29%; to Ory 5, in 29% of cases. Most often, patients are susceptible to sensitization to the allergen components of weeds Amb a 1 (30% of cases). Sensitization to beech trees was 17%. Sensitization to the cereal allergens was detected 2 times less often than to trees: 8% of patients were sensitized to the major component of the allergen of Timothy pollen Phl p 1. Most often, patients with helminthiasis were sensitized to food allergens. Of these, Bos d4 sensitization was detected in patient 1 (45%) and patient 4 (50%). Der f 1 demonstrates high sensitization in the patient in patients 6 and 3 up to 30%. Patient 2 exhibited a wide range of allergen sensitization, with significant values for Tri a 14 (35%), Mus a (15%), Bet v 1 (10%) and Phl p 1 (25%). High sensitization to Gal d 1 is observed in patient 3 (30%) and patient 5 (35%). These patterns of sensitization are associated with impaired immunity of intestinal mucosa in the patients with helminthic invasion, which, in turn, is a risk factor for development of sensitization to food allergens.

Chronic obstructive pulmonary disease (COPD) is one of the most common bronchopulmonary diseases. Eosinophilic inflammation of the respiratory tract in COPD requires further search for new markers for diagnosis and determination of further therapy strategy. Aim: determination of periostin level and assessment of its significance as a marker of eosinophilic inflammation in patients with COPD.

The study included 45 patients with COPD (males at median age of 65). Medical history, results of clinical and instrumental studies were evaluated. The levels of total IgE and periostin were determined in blood serum by enzyme immunoassay. The obtained data were processed using the software systems STATISTICA 13 and SPSS Statistical 27.

On the basis of peripheral blood eosinophils, the patients were divided into a group with eosinophilic inflammatory endotype (9 patients, males aged 67), and a non-eosinophilic endotype (36 patients, men aged 65 years). The patients with eosinophilic endotype of COPD had a later onset of the disease [64 (61-65) years vs 56 (49-60); p = 0.011], and a significantly higher proportion of patients with a history of atopy (80% vs 0%; p < 0.001). In patients with non-eosinophilic COPD endotype, a significantly lower FEV1/FVC index was found [46 (44-51) % vs 54 (54-73) %; p = 0.019]. The serum periostin level in patients with the eosinophilic endotype of COPD was 21 (20-22) ng/mL thus being significantly higher than in the group with the non-eosinophilic endotype [14.5 (12-18) ng/mL; p = 0.008]. Using ROC analysis, it was found that a periostin value of more than 19.5 ng/mL is the optimal cut-off point for detecting the eosinophilic endotype in patients with COPD thus serving an additional potential predictor of a positive response to inhaled glucocorticosteroid therapy (ICS) [AUC was 0.940 ± 0.060 with 95% CI: 0.822-1,000, sensitivity of 80%, specificity of 80% (p = 0.007)].

Periostin is a promising marker of eosinophilic inflammation in patients with COPD. Its elevated level may be considered an additional criterion for the administration of ICS therapy.

Antinuclear antibodies (ANA) are a family of autoaggressive antibodies directed against different components of the nucleus and cytoplasm of cells. The detection of ANA is of primary importance for the laboratory diagnosis of autoimmune diseases (AID). The aim of our study was to compare the presence of specific antinuclear antibodies with different types of antinuclear factor luminescence in children with autoimmune diseases using the HEp-2 test cell line. The study included 40 children (34 girls and 6 boys) with AID who were being treated at the National Medical Research Center for Children’s Health. The age of the patients ranged from 6.28 to 17.99 years. All children were diagnosed with antinuclear factor (ANF) on the HEp-2 cell line (epithelial cells of human laryngeal cancer) by means of indirect immunofluorescence reaction (AESKUSLIDES^® ANA-HEp-2, Germany) using a HELIOS^® analyzer (AESKU.GROUP, Germany). ANA was determined using a Q-Processor analyzer using Protea ANA Profile 18 panels (ProteomeTech Inc., Korea), which applies the immunoblot analysis method for the qualitative detection of autoantigen-specific IgG antibodies. A positive ANF titer was detected on the HELIOS^® analyzer in all children with AIS (100%). Using the Protea ANA Profile 18 panel, specific ANA was identified in 75% of patients (30 children). In our sample of children with AID, homogeneous (AC-1) and nuclear large-granular (AC-5) types of ANF luminescence, as well as their combinations, were most often detected. In the homogeneous type (AC-1) of ANF glow, autoantibodies to dsDNA, Nucleosome and Histone were more often detected. In large-granular nuclear (AC-5) antibodies to RNP 70, RNP A and RNP/Sm were determined, in combination with AC-1 + AC-5 – to SSA 60, SSA 52, Nucleosome and Histone, RNP 70, RNP A. We identified single points in the nucleus (AC-7) in 10% (4 children), this type of ANF glow is characterized by a low positive prognostic value. The study of ANF and specific ANA using the Protea ANA Profile 18 panel revealed a coincidence in 75% of cases, and certain ANA are consistent with the types of ANF luminescence. In pediatric diagnostics, it is advisable to determine a wide range of ANA when detecting antinuclear factor on the Hep-2 cell line.

Osteoarthritis (OA) is one of the most common diseases of the musculoskeletal system, accomplished by a high level of disability. The leading pathogenetic factors of these age-associated diseases include the interrelated processes of “inflammatory aging” and mitochondrial dysfunction, which lead to the development of chronic inflammation and degradation of different joint tissues. The present article contains results about point mutations in mitochondrial genome of peri-articular muscular tissues in the patients with primary OA (experimental group) and post-traumatic osteoarthritis (control group). The study involved 67 volunteers over 53 years old with basic diagnosis of post-traumatic or primary gonarthrosis / coxarthrosis stage 3. Clinical diagnosis was made on the basis of medical history, complaints, clinical and X-ray examination data. The material for the study included the samples of muscles (80 to 100 mm³) obtained at knee or hip replacement surgery. Several techniques have been adapted for isolation, enrichment and purification of nucleic acids, thus allowing to obtain up to 500 ng of mitochondrial DNA (mtDNA) from the biopsies. The prepared mtDNA libraries were sequenced at NGS platform. Bioinformatic analysis was carried out using the following programs: MitoHPC (to detect rare single-nucleotide mutations of mtDNA), MitoSAlt (to detect rare deletions at the mtDNA level) and Splice-Break2 (to detect rare deletions at the level of mtDNA RNA transcripts). Common point mutations A189G (adenine to guanine at position 189) and T408A (thymine to adenine at position 408) were detected. In the control group, the A189G mutation was revealed in 7 patients and T408A mutation was found in 8 volunteers (both mutations were detected in 6 out of 9 persons). In experimental group, the A189G mutation was found in 43 of 58 patients, T408A – in 35 volunteers. In this group of volunteers, both mutations were registered in 19 subjects. The level of mutation frequency, expressed as allele frequency (VAF) in the experimental group significantly exceeded that of the control group. Moreover, in experimental group, unlike control group, a significant correlative relationship was established between the presence of an increased level of mutations in the mitochondrial genome, and a number of clinical and laboratory parameters in volunteers. The described mutations in the mitochondrial genome of periarticular muscle tissue seem to be associated both with aging process and with the direct development of age-associated pathology, i.e., osteoarthritis. The increased levels of mutations in positions 189 and 408 of the regulatory region of mitochondrial genes detected in our patients are apparently associated with both increased level of mutations typical of pathological aging and, possibly, with genotoxic effects of high-dose therapy with non-steroidal anti-inflammatory drugs on mitochondrial genome.

Current research in the field of an immunogenetics of tuberculosis is considered a key direction, since the treatment efficiency and outcomes of the disease in most cases depend on immunological and genetic features of the patient. Special attention should be paid to IL-10 value in development of protective immunity against tuberculosis. There are some contradictory data on influence of IL-10 on development of immune response in the patients with pulmonary tuberculosis which are published in several works. For example, L.G. Tarasova and colleagues connect the increased concentration of IL-10 with extensive destructive processes in pulmonary tissue, whereas while D. Higgins and coauthors show its key role in protection against chronic pneumonia. The objective of our study was to evaluate relations between several cytokine gene polymorphisms (IL1β, IL4, IL10, TNF), and their expression levels of in the course of continuous chemotherapy.

Whole venous blood was taken for the molecular and genetic analysis was perfoemed, with subsequent isolation of genomic DNA and carrying out real-time PCR for genotyping of SNPs. Concentration of cytokines in blood serum were defined by method of enzyme immunoassay. Statistical analysis included check of normality of distribution of data, nonparametric correlations and comparison of qualitative characters. The assessment of compliance of genotypes to distribution of Hardy–Weinberg was carried out with use of criterion χ² Pearson. To measure the cytokine concentrations (IL-1β, IL-4, IL-6, TNFα, IFNγ, IL-10) in blood serum, we used peripheral venous blood taken in fasting state at a 5-mL volume. Enzyme immunoassay was made with reagent sets from JSC Vektor Best-Tsitokiny according to the instructions from manufacturer.

In the course of specific chemotherapy at the continuation phase, a more adverse course of a disease was registered among the patients with a pulmonary tuberculosis harboring IL4-589CC genotype, when compared with those who have IL4-589CT+TT genotype. In the persons with IL10-592CA+AA genotype, a less favorable course of the disease was observed at the intensive phase of therapy, in comparison with patients who had IL10-592CC genotype.

Thus, process of interaction between microorganisms and macroorganisms in case of a tuberculosis infection represents a quite complicated process involving a set of immune response elements. Interactions within this system are controlled by means of cytokines, the mediators of cellular interactions.

The damage to the immune system during HIV infection is of systemic oriigin, manifesting by deep suppression of the T- and B-links of cellular immunity. Particular importance in the normal functioning of all physiological systems is given to microelements, which are cofactors of at least 2000 enzymes that catalyze multiple biochemical reactions. Our study concerned measurent of 26 macro- and microelement contents in the hair of HIV-infected patients. It was carried out using the method of neutron activation analysis at the Institute of Nuclear Physics at the Academy of Sciences of the Republic of Uzbekistan. The parameters of immunity were evaluated in 50 patients with HIV infection at the Institute of Human Health (Academy of Sciences of the Republic of Uzbekistan). A significant decrease in Cl, Ca, K, Zn, Fe, Cu, Se, Cr, Ag, Co, Au, Ni, Sr, Ba, Hg, Sb, Cd, Rb was revealed in the group. Correction of this condition in HIV-infected persons and macro- microelement status was attempted using Spirulina microalgae as a dietary supplement, a product of natural origin. An analysis of Spirullina tablets was carried out, and the contents of 23 macro-microelements have been specified. The results of our study showed that clinical condition and quality of life was improved in 84% of patients after a month of taking Spirulina. Their physical performance was increased, general condition has been improved, and according to the patients, “the vital tone has increased.” Indices of immune status and contents of macro-microelements have been also improved.

The COVID-19 pandemic, which began in December 2019, was caused by the new coronavirus SARS-CoV-2. SARS-CoV-2 is a shell virus containing a single positive chain genome and using angiotensin converting enzyme 2 (ACE2) as a cell entry receptor. The targeting of SARS-CoV-2 on several tissues expressing ACE2 explains the multifactorial pattern of symptoms: fever, dry cough, myalgia, fatigue and shortness of breath. These symptoms do not always stop after COVID-19, and symptoms may reappear within 12 weeks, which indicates the development of post-COVID syndrome (long COVID). Due to the extensive symptoms and comorbidity of patients, the clinical diagnosis of post-COVID syndrome is difficult. The aim of the study is to identify pathognomonic indices of biochemical blood analysis in convalescents, indicating the development of post-COVID syndrome.

Patients and study design: a retrospective observational one-moment study of 373 case histories and outpatient records was conducted for the patients exposed to COVID-19 not later than 12 weeks ago. The initial course of the disease (disease) was assessed using the WHO Clinical Progression Scale. The severity of post-COVID syndrome (clinical outcomes) was assessed on the functional status scale after COVID-19 (PCFS). All subjects are divided into four groups, the names of which reflect the severity of COVID-19 and the severity of the post-ovoid condition: 1^st group, “mild COVID-19 / 0-2 PCFS class”; 2^nd group, “mild COVID-19 / 3-4 PCFS class”; 3^rd group, “medium and severe COVID-19 / 0-2 PCFS class”; 4^th group, “medium and severe COVID-19 / 3-4 PCFS class”. The sample was described by calculating the median (Me) values and interquartile range expressed as Q₁ and Q₃ (Q_0.25-Q_0.75). The reliability of the differences between independent samples was assessed with nonparametric Mann–Whitney U-test and the Student’s t-test.

Upon evaluation of clinical blood biochemistry, the alanine aminotransferase (ALT) level in group 1 was higher than in groups 2 and 4, the aspartate aminotrasferase (AST) level in group 2 was higher than in groups 1 and 3. The indexes of total cholesterol and LDL did not show statistically significant differences between the groups. Creatinine levels in group 3 are higher than in group 1, being lower in group 4 than in other groups. Significant differences were observed upon qualitative assessment of C-reactive protein (CRP). There were 2-3 times more subjects with elevated CRP levels in groups 2 and 4 than in group 1.

A minimal biochemical profile, including an assessment of the level of transaminases and creatinine, a qualitative or quantitative assessment of C-reactive protein, may indicate development of chronic inflammation. Patients of this group need to undergo an additional examination, e.g., general urine analysis and determination of albumin level in urine, dynamic GFR calculation, in order to prevent the development of persistent renal impairment.

The purpose of this study was to evaluate the level of cytokines in the blood serum of patients with acute coronary syndrome (ACS) who had and did not have COVID-19 in the dynamics of the disease and treatment. Our objectives were as follows: To identify groups of patients with ACS who had previously suffered from COVID-19 and who did not have this disease; to determine cytokine levels initially and over time in 2 groups of patients, i.e., those with and without previous COVID-19. Measurement of cytokine levels was carried out in 20 male patients with ACS without a history of COVID-19 and ACS patients with post-COVID syndrome. The contents of cytokines were determined by multiplex analysis on a MagPix 100 device using a test system from BioRad (USA) for 17 cytokines. As based on the data obtained, one may note that in patients who recovered from COVID-19, compared with persons without previous COVID-19, IL-10, IL-1β, IL-8 levels were significantly lower, and IL-13, IL-6, MCP-1 contents were increased. In the course of time, a statistically significant decrease (p < 0.05) was found in patients who had previously had COVID-19 for IL-10, IL-13, IL- 2, IL-6, MCP-1, MIP-1β, TNFα, whereas IL-8 levels were increased (p < 0.05). In patients without a history of COVID-19, a statistically significant decrease was revealed in dynamics for IFNγ, IL-6, MCP-1, MIP-1β, TNFα, along with increase in IL-8 contents (p < 0.05). Patients with post-COVID syndrome, compared with those without a history of COVID-19, had a higher content of pro-inflammatory cytokines, in particular, IL-6, IL-8, MCP-1. In the time dynamics after complex therapy (drug and stenting of coronary arteries), there was an improvement in some indices 28 days later. In particular, in both groups (those previously ill, versus not exposed to COVID-19), the following pro-inflammatory cytokines were decreased significantly (p < 0.05): IL-6, IL-8, MCP-1, MCP-1β, TNFα. Meanwhile, the anti-inflammatory cytokine IL-10 was increased (p < 0.05). Hence, the disturbances in regulation of immunity and, first of all, in chemokine parameters, were obtained in the patients with post-COVID syndrome and ACS, in contrast to the persons with ACS who was not previously affected by COVID-19. In patients with acute coronary syndrome who have recovered from COVID-19, we have found a more pronounced disruption of cytokine regulation of immune system than in patients who did not suffer from the coronavirus infection.

Antibiotic-associated diarrhea (AAD) is one of the most significant complications of antibacterial treatment. The objective of the study was to provide a clinical case of C. difficile-associated enterocolitis in a child. Case description. A clinical case of moderate enterocolitis caused by C. difficile is presented in a 4-year-old child who fell ill while taking 3 courses of antibiotics (cefotaxime, claptrithromycin, amikacin), which manifested as abdominal pain, false attempts to defecate, frequent scanty mucous stool with blood admixture, fever. At the same time, negative results were obtained from bacteriological stool culture for enteropathogenic microflora and stool testing for intestinal viruses using ELISA and PCR; a questionable result was obtained at stool testing for the type A and B C. difficile toxins. A general blood test showed neutrophilic leukocytosis and a left shift in the differential leukocyte counts, inflammatory changes in the coprogram, thickening of the colon wall up to 3-4.5 mm according to ultrasound data, enlarged mesenteric lymph nodes were found. Upon anti-infectious therapy with vancomycin and metronidazole, rapid positive dynamics of the child’s condition and recovery were noted. Conclusions. The diagnosis of C. difficile-associated infection should be established on the basis of a comprehensive analysis of available clinical, epidemiological, anamnestic, laboratory and instrumental data. Negative or questionable results of the test for C. difficile toxins A and B in feces does not exclude an infection associated with C. difficile.