Chicken egg is among the most important sources of allergens. Sensitization to them is most often manifests as food allergy (FA), and/or atopic dermatitis (AD). Immunogenic substances of a chicken egg are present in both white egg and yolk.The purpose of our work was to compare frequency and intensity of the IgE responses to various components of a chicken egg in children, depending on their age and gender. We examined 3070 children with symptoms of food allergies and atopic dermatitis, analyzed the IgE responses to chicken white egg allergens extract (f1) and yolk allergens extract (f75), taking into account the age and gender of children. The IgE levels were determined by immunofluorescence using an automatic ImmunoCAP 250 analyzer. We found a high incidence of sensitization to chicken egg in children with FA and AD: 31.07% (n = 954) of patients had clinically significant IgE levels. The frequency of sensitization to white egg was statistically significantly higher than the frequency of sensitization to yolk: 31.04% (n = 953) and 13.13% (n = 403), respectively. The maximum prevalence of positive IgE responses to white egg and yolk and more severe sensitization were observed in children of their first year of life. A significant decrease of these indices has been detected in groups of older children. In older age groups, there was also a decrease in the number of co-sensitized patients, whereas the number of monosensitization cases to chicken egg protein was increased in groups of children of 2 to 6 years old, and then decreased in children over 6 years old. The frequency of positive IgE responses to allergen extracts of white egg and yolk did not differ significantly and had similar age dynamics in children of both sexes. Statistically significant differences between the IgE responses of boys and girls were found only in groups of children over 14 years old, especially with IgE to allergens of white egg. We have shown an extremely low frequency of monosensitization to yolk: clinically significant levels of IgE to yolk in the absence of antibodies to egg protein were found in 0.1% of patients with food allergies and atopic dermatitis. High frequency of sensitization to chicken eggs in small children suggests an extremely early contact of the patients with allergens. The immunogenic ability of white egg and yolk allergens is different. Much more pronounced IgE response was observed towards white egg. A decreasing number of positive IgE response cases to chicken egg allergens in children may be due to development of immunological tolerance to both yolk and white egg at the age of 8-10 years. However, the issue of studying the allergic response mechanisms remains open, since, despite a significant decrease in prevalence of egg allergy in older children, a number of patients still do not achieve tolerance to this food product.

Liver diseases cause about 2 million deaths per year worldwide, with cirrhosis accounting for 2.1% of this number. The cytokine and chemokine balance determines outcomes of immune response. Many cytokines are involved in progression and control of various liver diseases via regulation of cellular activity. Our aim was to assess the level of circulating cytokines and chemokines depending on the stage of fibrosis in children with chronic liver diseases. 51 children with chronic liver diseases were examined (32 children with autoimmune hepatitis, 12 children with Wilson’s disease, 5 children with Gaucher disease and 2 children with glycogen storage disease). All children were assessed for the stage of liver fibrosis (AF) using METAVIR scale (FibroScan F502). The contents of circulating serum cytokines, chemokines, growth factors and angiogenesis was determined by the MILLIPLEX® Human Cytokine/Chemokine/Growth Factor Panel A Magnetic Bead Panel, an immunoassay based on Luminex® technology. Statistical evaluation was carried out using the program “Statistica 10.0”. The levels of EGF, Fractalkine, IFNá, IL-10 and MIG increased significantly from F0 stage to F4 stage. A significant decrease from stage F0 to stage F4 was revealed for eotaxin, IL-5, IL-8, IL-17A. Some cytokines were characterized by nonlinear dynamics: the concentrations of IL-4 and MDC increased significantly from the F0 stage to the F2-3 stage, and then decreased to the F4 stage; the level of IL-18 showed a significant decrease by stage F2-3 relative to F0, then being significantly increased by stage F4. The level of TNFáwas increased at all stages of liver fibrosis and reached its maximum values at stage F2-3 of AF. Our data confirm the significant role of cytokines and chemokines in the pathogenesis of chronic liver diseases. The identified changes in circulating cytokines in the blood serum in children with CKD, depending on the stage of fibrosis, are characterized by differently directed disturbances thus presuming involvement of both pro- and anti-inflammatory mechanisms in the immunopathological process in the course of liver fibrosis formation. Further research is required in order to study the participation of cytokines and chemokines in formation of liver fibrosis for development of targeted therapy for liver diseases.

Multiple sclerosis (MS) is a chronic, demyelinating disease that leads to disability. Understanding the etiology of MS contributes to the development of pathogenetic methods of treatment, and the search for informative biomarkers of the effectiveness of treatment will allow the patient to adjust therapy in time. The aim of this work was to determine informative cytokines and cytokine profiles to predict the effectiveness of IFN-β1a therapy in children with MS.Materials and methods. 66 children with MS aged 16 [14.2–17.5] years who are on INFß-1a therapy were examined: group 1 — patients with exacerbation of MS (with active foci of demyelination by MRI), n = 34; group 2 — patients in remission of MS (without active foci), n = 32. The content of cytokines in the blood serum of patients was assessed using the multiplex panel Human Th17 Magnetic Bead Panel.Results: There was a significant increase in cytokine concentrations in patients with exacerbation of MS compared with children in remission: IL5, IL6, IL9, IL12p70, IL17E/IL25, IL21, IL28A, GM-CSF, TNFß. Threshold values for IL9 (AUC = 0,785), IL6 (AUC = 0,750), TNFß (0,740), IL28A (AUC = 0,744) were obtained above which it is possible to predict an exacerbation of MS in patients: IL9 — 3.9 pg/ml (Sn — 70.6, Sp — 71.9), IL6 — 4.0 pg/ml (Sn — 70.6, Sp — 68.8), TNFß — 6.6 pg/ml (Sn — 70.6, Sp — 71.9), IL28A — 243.0 pg/ml (Sn — 70.6, Sp — 71.9). Cytokine profiles associated with T-lymphocytes and their functions were evaluated using z-score.Conclusions. For the first time, an increase in cytokine levels was demonstrated in children with active foci of demyelination compared to patients in remission of MS. An increase in proinflammatory cytokines and cytokine profiles associated with Th1 and Th17, as well as with Th2 and Th22 has been shown. The use of threshold values for IL9, IL6, TNFβ, IL28A will help predict the development of exacerbation in patients with MS.

In recent decades, there has been an increase in the incidence of autoimmune diseases (AID) among adults and children. The immunopathogenesis of AID is based on an imbalance between autoaggressive and regulatory cells (Tregs), which is regulated by metabolic signaling pathways and the cytokine microenvironment. Understanding the mechanisms of immunometabolism opens up new possibilities for the treatment of patients with AID. The aim was to evaluate the activity of lymphocyte dehydrogenases associated with OXPHOS and glycolysis, depending on the level of proinflammatory and anti-inflammatory cytokines in children with AID.324 children with AID were examined: 80 – Crohn’s disease (CD), 53 – ulcerative colitis (UC), 89 – psoriasis (PS), 66 – multiple sclerosis (MS), 36 – autoimmune hepatitis (AIH). Activity of mitochondrial dehydrogenases (succinate dehydrogenase (SDH) and glycerol-3-phosphate dehydrogenase (GFDH)) were evaluated by immunocytochemical method using flow cytometry. The level of cytokines (CС) in blood sera was determined by multiplex analysis.In each studied group of children, CС with the highest values in exacerbation and remission of the disease were identified. The maximum values of CС were in patients with exacerbation: CD, UC, PS, MS – IL-23; AIH – IL-27. Evaluation of cytokine complexes associated with cells showed significant differences between patients in exacerbation/remission: CD, UC and PS – M1(IL-1+IL-6+TNFα), cTh1(IFNγ+IL-12p70+TNFβ+IL-2), cTh2 (IL-4+IL-5+IL-10+IL-13+IL-17E/IL-25+IL-33), cTh17 (IL-1β+IL-6+IL-17A+IL-17F+IL-21+IL-22+IL-23); MS – M1, cTh1, cTh2; AIH – cTh2. SDH activity in AID remission differed between pathologies in CD4+ cells, Th17 and Tregs. In exacerbation of AID, there were differences in Tregs between patients with UC and PS. The highest GPDH activity in exacerbation was observed in CD4+ lymphocytes, Th17 and Tregs in CD. The ratio of SDH/GPDH in T-lymphocytes in children with CD in exacerbation and remission was lowest and significantly lower than in UC, PS, MS, AIH and apparently healthy children. In the group of children with a low SDH/GPDH ratio, the levels of CCL20/MIP3α, IFNγ, IL-12p70, IL-13, IL-17A, IL-1β, and TNFα were significantly increased. Conclusions. Informative cytokine complexes were identified in children with AID. The relationship between the metabolic activity of lymphocytes and the level of circulating cytokines is shown.

Gaucher disease (GD) is an autosomal recessively inherited disease that belongs to the group of lysosomal storage diseases. In GD, there is chronic activation of the macrophage system, disruption of the regulatory functions of macrophages, a shift in cytokine regulation towards pro-inflammatory cytokines and the development of chronic inflammation involving all immune cells, which can lead to changes in the composition of both major and minor populations of lymphocytes. Reduced beta-glucocerebrosidase activity impairs normal lysosomal function and autophagy, leading to the intracellular accumulation of glycosphingolipids, creating a self-sustaining cycle of impaired glucocerebroside utilization with the aggravation of both lysosomal and mitochondrial functions. It is known that untreated patients with GD are susceptible to more frequent and complicated infectious diseases, which presumably may arise due to changes in the functional activity of neutrophils caused by the disruption of the process of phagocytosis and oxidative burst in this cell population. The aim: to study the age-related features of the composition of the major and minor populations of peripheral blood lymphocytes, the activity of intracellular dehydrogenases of lymphocytes and the functional activity of neutrophils in children with GD. The study was approved by the Independent Ethics Committee and the Scientific Council of the National Medical Research Center for Children's Health of Ministry of Healthcare of the Russian Federation. The study included 73 children with GD, of which 26 children were examined at different age periods (1 child – 4 tests, 3 children – 3 tests, 22 children – 2 tests), the comparison group consisted of 148 healthy children comparable in age. The determination of the subpopulation composition of lymphocytes, the study of succinate dehydrogenase activity in the major and minor populations of lymphocytes (by immunocytochemical method) and the assessment of the functional activity of neutrophils were carried out using flow cytometry. The parameters of lymphocyte subpopulations were analyzed as percentage deviations from the age norm. The activity of intracellular dehydrogenases (succinate dehydrogenase, NADH dehydrogenase, lactate dehydrogenase) was determined by a cytomorphodensitometric method using image analysis. The statistical calculations were performed using the Statistica 10.0 program (StatSoft, USA). A decrease in NK cells and an increase in Th17 cells and activated T helper cells are usually observed in children with GD with age. The analysis of the activity of intracellular dehydrogenases revealed a decrease in the processes of oxidative phosphorylation and glycolysis in peripheral blood lymphocytes in children with GD. The functional activity of neutrophils in the majority of children with GD corresponded to the reference values.

Metabolic aberrations underlie many chronic diseases, including autoimmune diseases (AUD). Immune metabolism is an area of immunological research that is actively developing and studying the processes of metabolic reprogramming in immune cells. The regulation of the nuclear factor kappa B (NF-κB) activity, which is involved in the coordination of innate and adaptive immunity, inflammatory reactions and other processes, is being actively studied. The studies on immune metabolism and regulation of NF-κB is a promising direction in searching for new therapeutic approaches in the AUD treatment. The aim of the present study was to evaluate the informative value of NF-κB and the activity of intracellular lymphocyte succinate dehydrogenase (SDH) and glycero-3-phosphate dehydrogenase (GPDH) determined in children with immune-dependent disorders. 350 children with autoimmune diseases were examined: 97 patients with IBD, 72 children with relapsing-remitting multiple sclerosis (MS), 83 pediatric patients with psoriasis vulgaris (PS), and 97 children with autoimmune hepatitis (AIH). The comparison group consisted of 100 conditionally healthy children. Activity of mitochondrial dehydrogenases, i.e., SDH and GPDH, was evaluated by immunocytochemical method. The levels of NF-κB translocation (per cent of cells with NF-κB translocation from cytoplasm to cell nucleus) was determined by flow cytometry, with visualization. Statistical evaluation and plotting were carried out using the Statistica 13.0 software. The highest activity of SDH and GPDH was detected in the population of cytotoxic T lymphocytes and T helper cells, and the lowest activity of the enzymes was registered in the population of B lymphocytes, both in children with AUD and in comparison group. In children with AUD, there was a significant decrease in SDH activity in T lymphocytes, cytotoxic T lymphocytes, B lymphocytes and NK cells against the comparison group (p 0.01). In children with PS, AIH and IBD, a decrease in SDH activity was revealed in Treg and Th17 cells. The most pronounced decrease in GPDH was characteristic of patients with AH (in T cells, cytotoxic T lymphocytes, B cells, NK cells and Tregs against the comparison group). In children with PS, the activity of GPDH was reduced only in Tregs (p 0.05). For children with multiple sclerosis, a decrease in GPDH was revealed in populations of T lymphocytes, B lymphocytes and activated T helpers (p 0.01). In the group of patients with IBD, there were no significant differences in the activity of GPDG relative to the comparison group. A significant increase in the level of NF-κB translocation in T helpers was revealed in all children with AUD relative to the comparison group. In children with AIH and PS, a significant increase in the level of NF-κB translocation was revealed in Treg, Thact and Th17 cells, in children with MS it was found in Treg cells, in patients with IBD, it was registered in Thact against the comparison group (p 0.05). An inverse correlation was found between the levels of NF-κB translocation in lymphocyte populations, and activity of mitochondrial dehydrogenases in the lymphocytes. The most significant dependencies are characteristic of NK cells and T cell populations, and these correlations are valid for all groups of AUD patientsh. In the course of in vitro experiments with a drug of metabolic action, a decreased number of cells with NF-κB translocation and an increased SDH activity was observed; the degree of SDH activation depended on the cell population type, the greatest changes were detectable in the population of T lymphocytes (by 61%), in B lymphocytes (by 30%), in NK cells (by 19%). The study of the metabolic activity of lymphocytes and the NF-κB signaling pathway allows us to assess the general mechanisms of immunopathological processes in children with autoimmune diseases of various etiologies. As based on the inverse correlation between the level of translocation of NF-κB and the activity of SDH in lymphocytes, one may consider the use of an available immunocytochemical method being an analogue for assessing activity of the NF-κB transcription factor. The studies of immune metabolic correction of immunocompetent cells are a promising direction in the AUD treatment.

Severe mechanical injury is among the main reasons of disability and mortality in pediatric patients. The imbalance between the states of inflammation and immune suppression during the critical period of post-traumatic injury bears an elevated risk for infectious complications and/or multiple organ failure. The present study aimed to determine the informative immunological criteria in order to evaluate severity and prognosis for clinical outcomes in children from the severe injury group (SInj, ISS 16, n = 87); mild/moderate injury group (MInj, ISS 16, n = 34), as based on assessment of helper T cells (Th) ratios, i.e., Th17/Treg, T127hi/ Treg, and Th17/T127hi. The patients with severe injuries were classified by their outcomes (favorable, n = 47; unfavorable, n = 40), presence of infectious complications (IC, n = 16) and the development of multiple organ failure (MOF, n = 11). Th ratios were studied on the 1st, 3rd, 5th, 7th, 14th day after injury. For the Sinj group, a pronounced increase of Th17/Treg ratio in the acute post-traumatic period with a decrease by 14 days was revealed. The indices of T127hi/Treg ratio on the first day for the patients from Minj group corresponded to the values of control group and significantly differed from patients with SInj in the 3rd to 5th day. There are different kinetics of Th subset ratio in peripheral blood of children with severe injuries over time in different groups, as well as with/without MOF, in presence, or absence of infectious complications and different clinical outcomes. Significant differences in T127hi/Treg ratio level were found in group with IC from 1st to 3rd day and from 7th to 14th day. Significant differences in Th17/Treg ratio level were found in IC group (7th day), in MOF group on 14th day post-injury. The patients with MOF had lower median concentrations of Th17/Treg and T127hi/Treg than patients without MOF. The results of the study indicate that the levels of Th17/Treg and T127hi/Treg ratio in children may be used to predict outcome of the traumatic disease and assess the risk of infectious complications and multiple organ dysfunction syndrome.

Severe mechanical injury is one of the main reasons behind children’s disability and mortality. Severe injury induces a complex host immune response to tissue injury, a parallel pro- and anti-inflammatory state, bearing an elevated risk for infectious complications (IC) and/or multiple organ failure (MOF). This study aimed to determine the informative immunological criteria of traumatic injury severity and prognosis outcome in children (severe injury group (SInj, ISS ≥ 16), n = 87; mild/moderate injury group (MInj, ISS < 16), n = 34) based on the assessment of absolute cell count (abs) and percentage of such T helper subpopulations as regulatory T lymphocytes – CD4+CD127lowCD25high(Treg), Th17 lymphocytes – CD4+CD161+ and CD4+CD127higtCD25high T cells(T127hi) in severe injury cases grouped by the outcome (favorable, n = 47; unfavorable, n = 40) and depending on IC (n = 16) and the development of MOF (n = 11) on the 1st, 3d , 5th, 7th, 14th day after injury. The control group was comprised of 80 apparently healthy children comparable in age and sex. An inverse relationship between severity of injury, degree of blood loss and outcome of injury was revealed with the abs of all Th populations, but for Th abs and Treg abs the most significant correlation was found (Spearman’s R ≤ -0,70, p < 0.00001). For SInj group, a pronounced decrease of Th abs, Treg abs, T127hi abs and Th17 abs, in the acute post-traumatic period with an increase to 14 days was revealed. The values of in the first day for indicators of patients with MInj group correspond to the values of control group and significantly differ from SInj group. There are different kinetics of percentage Th subpopulations in peripheral blood of children with severe injuries. The Th17%CD4+ and T127hi%CD4+ significant increase in 1st-3d and 3d -7th days after injury respectively in comparation with сontrol and MInj groups. There were no differences between groups in terms of Treg%CD4+. The lower-level Treg abs in trauma patients admitted to the ICU is significantly associated with develop the infectious complications and outcome of trauma. The Th17 abs is significantly reduced in 3-7th days after the injury in the SInj group with MOF. The results of the study indicate that in children levels of Treg, T127hi and Th17 is significantly associated with severity of injury and may be used to predict outcome of trauma and assess the risk of IC and MOF.

Psoriasis is a chronic inflammatory skin disease characterized by increased proliferation of epidermal cells, impaired keratinization and an inflammatory reaction in dermis caused by activation of T lymphocytes and synthesis of pro-inflammatory cytokines. The pathophysiology of psoriasis is also associated with a decrease in anti-inflammatory functions of immunosuppressive cells. Recently, there are more cases of development of resistance to ongoing therapy with biologics in children, requiring cancellation of drug or its replacement. The aim of the study was to evaluate the content of T helper subpopulations in prognosis of effectiveness of biologics in children with psoriasis. Immunophenotyping of T helper populations was performed in 110 children with psoriasis vulgaris before appointment of biologics, at 16 and 52 weeks. Age of children ranged from 6 to 18 years. Severity of psoriasis and effectiveness of therapy were assessed by index PASI, which varied 0-68. Content of Tregs, Thact and Th17 was determined by flow cytometry. In group with a sufficient effect of biologics, a decrease in PASI was obtained, both at week 16 of therapy (p = 0.000) and by year of treatment, p = 0.017. In children with psoriasis, regardless of duration and effectiveness of biologics, percentage of Thact was increased relative to normal values. In group 1 before prescription of biologics was increased percentage of Thact (p = 0.005) and Th17 (p = 0.001). Analysis of dynamics of content of small populations of T helper during 1 year of use of biologics in children with different efficacy of therapy showed that significant changes were found in content of Th17 and Treg, as well as their Th17/Treg. ROC analysis showed that when Th17 deviation was above 53%, Thact above 181% and Th17/Treg above 2.6 before biologics were prescribed, insufficient efficacy of therapy could be expected in 75% of cases by year. By the end of induction course, with a Th17 deviation above 102% and a Th17/Treg above 2.6, probability of ineffective treatment was already 82%. The study shows the informative value of assessment of Thact before appointment of biologics, dynamics of Th17 by the end of induction course and Treg after 16 weeks of therapy in prognosis of effectiveness of biologics in children with psoriasis.

The article presents data on the content of albumin, ischemia modified albumin, protein frac-tions and 3-nitrothyrosine in the blood serum of children with different severity of inflamma-tory bowel diseases (IBD in remission and exacerbation). It has been shown that the more severe the condition, the more pronounced the decrease in albumin. On the contrary, the content of acute phase proteins, modified albumin and 3-nitrothyrosine (NT) increases with increasing severity of IBD.

In connection with the increasing incidence and prevalence of inflammatory bowel disease (IBD), the search for prognostic markers of the effectiveness of therapy is an urgent problem. An imbalance between Th17 lymphocytes and regulatory T cells (Treg) is a major defect in the immune system leading to IBD. Extracellular ATP produced during tissue damage, rebound pro-inflammatory effects, and activates Th17 cell differentiation. Ectonucleotidase CD39 catalyzes the dephosphorylation of ATP to AMP, followed by conversion to adenosine by CD73. CD39 is expressed in various cell types, including Treg. Aim – evaluate the functional activity of CD39+ in Treg in children with IBD using the luciferin-luciferase method.68 children with IBD were examined. Of these, 28 children were in remission, 40 were in exacerbation. The number of Tregs (CD4+CD25highCD127low) expressing CD39 was estimated by flow cytometry. The ATP concentration in supernatants and cells was determined using the luciferin-luciferase test. Results are presented as median (Me) and quartiles (Q0.25-Q0.75). The significance of differences between groups was assessed using the nonparametric Mann–Whitney U test.The relative number of CD39+Treg in patients in remission of IBD was significantly higher than in patients in a state of exacerbation. A decrease in ATP concentration under the influence of CD39+Treg in patients with IBD occurred immediately upon the addition of exogenous ATP. ATP in patients in remission decreased by 44.5% (Me 54.5 (41.5-65.9)), in patients in exacerbation – by 32.5% (Me 67.5 (59.7-71.3)). At the same time, in patients in remission, the decrease in the ATP content after 5 minutes of the reaction was significantly higher than in patients in the state of exacerbation (p = 0.01), after 30 minutes of the reaction, no significant difference was found. It was shown that samples with a smaller number of cells and a lower intensity of CD39 expression in Treg had a higher activity of CD39 ectonucleotidase.For efficient ATP hydrolysis, in addition to the amount of CD39 in Treg, their functional activity is important. The assessment of the catalytic activity of CD39 in Treg in patients with IBD is most informative in the first minutes after the addition of exogenous ATP. In patients in remission, the catalytic activity of CD39 in Treg was higher than in patients in a state of exacerbation.

Wilson's disease (WD) is a rare hereditary disease caused by a deficiency of the ATF7B transporter. The accumulation of copper can cause damage to organs and cells, mainly the liver. Copper exposure can modulate cytokine synthesis through molecular and cellular signaling pathways, including the nuclear transcription factor NF-kB pathway. NF-kB is the main regulator of inflammation and cell death, acts as a central link between liver damage, fibrosis and hepatocellular carcinoma. An excess of NF-kB-dependent cytokine response stimulates inflammatory reactions, but excessive inhibition of NF-kB can negatively affect the viability of hepatocytes. Method of flow cytometry with visualization — Amnis ImageStreamX allows to evaluate the activity of NF-kB (% of activated cells in cell populations). The aim: to evaluate the activity of NF-kB in lymphocyte populations in children with WD disease. Immunophenotyping of lymphocytes and assessment of the level of translocation of NF-kB were performed in 52 children with WD and in 25 children of comparison group. The mass concentration of copper in daily urine was determined by atomic absorption method using the AAnalyst 800 spectrometer. In children with WD, the content of cells with NF-kB translocation varied from 5 to 90% depending on the lymphocyte population; the highest level was detected in B cells — 57.5 (37-68) %. A significant difference in distributions of the number of cells with NF-kB translocation between WD and healthy children was shown (F-criterion, p < 0.01). In most cases, children with WD are characterized by a decrease in the activity of NF-kB in populations of B cells (in 43% of cases), T helper cells (48%), T cytotoxic (44%) and Th17 lymphocytes (41%). In children with WD, the concentration of copper varied from 9.7 to 2582 mcg/day, Me = 616 (210-1173). A direct relationship was obtained between the copper content in urine and the level of translocation of NF-kB in B lymphocytes, r = 0.34, p = 0.016. The activity of the NF-kB correlates with biochemical markers of the severity of liver damage (ALT, AST, GGT) and with copper content in urine. The study of the NF-kB signaling pathway seems promising for a better understanding of the pathogenetic mechanisms of the formation of inflammation and liver fibrosis in children with WD.

MS is a common disease of the central nervous system that leads to disability and reduced quality of life. The debut of disease in 3-5% of patients occurs in childhood and has a less favorable course compared to adults. MS is caused by the activation of autoreactive T cells in the breakdown of peripheral tolerance, which is normally controlled by regulatory T cells (Tregs). It is promising to study expression of CD39 and CD73 in Treg and Th17 populations to assess their suppressive activity. Aim is to evaluate content of major and minor lymphocyte populations and expression of CD39 and CD73 in CD4+ lymphocyte population in children with MS. 111 children with MS were examined, 66 with contrast-negative lesions on MRI (Group 1), 45 with contrast-positive lesions (Group 2). The comparison group consisted of 46 healthy children (Group 3). Content of T, B, NK lymphocytes, Treg (CD4+CD25highCD127low), Thact (CD4+CD25highCD127high), Th17 cells (CD3+CD4+CD161+); expression of CD39 and CD73 in Treg, Th17 and Thact was performed by flow cytometry. An increase in content of T helpers, a decrease in NK cells in patients in group 2 was revealed. An increase in number of Thact and Th17 lymphocytes was obtained in patients of both groups with MS. Number of Tregs in group 1 was significantly higher than in group 3. Ratio of cells expressing CD39 and CD73 in MS patients depended on lymphocyte population as well as in the group 3. The highest content of CD39+ cells was observed in Treg population, and the lowest in Thact population. For CD73 expression, on the contrary, the highest expression of CD73 was observed in Thact cells, the lowest in Treg. When comparing groups of patients, it was found that in patients of group 1, number of cells expressing CD39 ectonucleotidase was significantly increased, and number of supTh17 was comparable with group 3. In both groups of MS patients, an increase in CD73 counts in Treg, Thact and Th17 was observed. Thus, informative populations of lymphocytes (CD4+ cells, Treg, CD39+Treg, supTh17) have been identified, which can be used to monitor condition of children with multiple sclerosis.