BACKGROUND:Heart transplantation (HT) remains the primary treatment for end-stage heart failure, but graft rejection-including acute cellular rejection (ACR), antibody-mediated rejection (AMR), and chronic rejection such as cardiac allograft vasculopathy (CAV)-significantly impacts long-term patient outcomes. This study investigates the role of circulating plasma extracellular vesicle profiles as potential biomarkers for distinguishing between different rejection types following HT. METHODS:We enrolled 85 HT patients with post-transplant follow-up ranging from 2 to 140 months. The cohort included patients diagnosed with AMR (n = 23), ACR (n = 11), CAV (n = 20), and those without rejection (R0, n = 31). Extracellular vesicle profiles were analyzed using the MACSPlex Exosome Kit, and associated cytokine profiles were assessed using the MILLIPLEX Human Cytokine Panel A. Statistical analysis involved the Kruskal Wallis test followed by Dunn's post-hoc test for multiple comparisons and discriminant analysis. RESULTS:Circulating plasma extracellular vesicle profiles demonstrated significant differences across post-transplantation time strata and varied according to the type of transplant rejection. During the first year post-HT, the main discriminant factors were extracellular vesicles (EVs) characterized by tetraspanins (CD9+, CD63+) and platelet markers (CD62P+, CD42a+). Five years post-transplantation, significant differences emerged in patients with AMR and ACR (both compared to each other and to the CAV/R0 groups). This difference corresponded with an increase in EV markers associated with immune cell activity (CD3+, CD4+, CD49e+, CD86+, CD20+, CD14+, CD209+, CD1c+, CD29+). Levels of prominent EV subpopulations correlated with IL‑22 in CAV patients, whereas in AMR patients, they correlated with IL‑17 and IL‑25. CONCLUSIONS:These findings support the hypothesis that extracellular vesicles may participate in both direct and indirect antigen presentation and in the regulation of immune responses leading to allograft rejection after HT. Plasma extracellular vesicle profiles hold promise as non-invasive biomarkers for monitoring and differentiating rejection types in heart transplant recipients.

BACKGROUND Necrotizing enterocolitis (NEC) remains a prominent gastrointestinal emergency among infants, particularly term infants with congenital heart defects (CHD) being at high risk. The molecular processes that contribute to NEC have yet to be completely understood. The high mortality rates necessitate an active search for noninvasive biomarkers that can aid in the preclinical diagnosis and prognosis of NEC. MicroRNAs (miRs), which are involved in many biological processes in both health and disease, have been discovered to play an important role in regulating inflammation and immune responses via various signaling pathways. AIM To determine the plasma levels of miR-155, miR-221, miR-223, miR-320a, miR-451a as potential NEC biomarkers in term newborns with CHD. METHODS This prospective cohort study included twenty-tree term newborns with CHD who underwent cardiac surgery on the median day of life (DOL) = 7. Nine of them developed NEC (Bell’s stage IIA and IIIA) within 1 week of cardiac surgery (NEC newborns). Blood samples were collected before (median DOL = 5) and following (median DOL = 13) cardiac surgery. Levels of plasma miR-155-5p, miR-221-3p, miR-223-3p, miR-320a-3p, and miR-451a were determined using real-time polymerase chain reaction. The functional analysis was executed using the DIANA-miRPath v4.0. RESULTS Preoperatively, NEC newborns had significantly lower plasma levels of miR-155 (2.70-fold, P = 0.020), miR-223 (2.42-fold, P = 0.030), and miR-320a (3.62-fold, P = 0.006) than newborns without NEC. Postoperatively, miR-451a levels differed significantly between the newborn groups, showing a 4.70-fold decrease (P = 0.014) in expression when clinical NEC symptoms appeared. According to receiver operating characteristic analysis, miR-320a was found to be the most effective predictive biomarker for NEC [area under the curve (AUC) = 0.835, 63% sensitivity, 100% specificity], while miR-451a was identified as a NEC biomarker (AUC = 0.835, 85.7% sensitivity, 76.9% specificity). Preoperatively, miR-155-5p, miR-223-3p, and miR-320a-3p were differentially expressed and targeted the forkhead box O and Hippo pathways (P < 0.01). CONCLUSION Our study demonstrates, for the first time, that plasma miR-320a-3p levels can be used as a preclinical biomarker for NEC in term newborns with CHD.

The pathogenesis of NEC in term infants with critical congenital heart defects (CHD) is mainly associated with hypoxic-ischemic events that initiate an exaggerated systemic inflammatory response. Herein, we investigated the cumulative impact of the cytokine landscape and gut microbiota on the pathobiology leading to NEC onset in term newborns with CHD. This study involved 36 newborns who underwent surgical correction of CHD during the first two weeks of life; eight of them developed NEC within one week after cardiac surgery. Blood and fecal samples were collected at two time points: before and after surgery. Newborns without NEC exhibited significant changes in the levels of 22 cytokines, whereas newborns with NEC had changes in only 4 cytokines during the perioperative period. A panel including IL-1RA, IL-5, IL-18, and MCP-1 showed impressive test performance characteristics for diagnosing NEC at the preclinical stage with an AUC of 0.938, a sensitivity of 100.0%, and a specificity of 85.7%. Fifteen bacterial taxa were differentially abundant between feces samples of newborn groups. The pathobionts Collinsella and Mediterraneibacter gnavus group, known to be associated with increased intestinal permeability, were enriched in NEC newborns’ feces before cardiac surgery. Our study demonstrated that the gut microbiota mediates the equilibrium of cytokine network dynamics under a broad spectrum of “friend or foe” conditions, effectively suppressing excessive inflammatory responses during early postnatal adaptation. In contrast, under conditions of low microbial diversity, a strong imbalanced cytokine feedback loop formed, resulting in deviations from normal immune response maturation. These findings offer new insights into understanding the fine-tuning of gut microbiota-immune system interactions in the first days of life.

Background/Clinical Significance: Development of acute antibody-mediated rejection (AMR) of allograft is one of the leading causes of mortality in heart-transplant recipients; however, the standard therapy does not always resolve severe forms of rejection. Extracorporeal photopheresis (ECP) is a method of immunomodulatory therapy that involves separating a patient’s white blood cells and treating them with a photosensitizer and ultraviolet A irradiation. Case Presentation: An 18-year-old female patient was urgently hospitalized with complaints of shortness of breath. She had undergone heart-transplant surgery 9 months before due to congenital heart disease restrictive cardiomyopathy, complicated with end-stage chronic heart failure. During the admission she admitted that for 3 weeks she discontinued tacrolimus and mycophenolate mofetil. AMR3 and CAV were verified. Conclusions: The use of standard approaches in the treatment of acute AMR is not always able to suppress an expressed immune reaction against the cardiac allograft, which leads to disruption of its function and rejection in the early or long-term follow-up. The inclusion of ECP in the treatment regimen allowed us to stabilize the patient’s condition and achieve regression in the severity of the AMR. It is believed that an important role in this was played by the activity of the immune system, which we assessed by changing the profile of cytokines, chemokines, and other growth factors. Thus, ECP demonstrated its effectiveness in the treatment of AMR of the cardiac allograft, with a change in the severity of the cytokine storm, as well as with an increase in the contribution of cytokines associated with the Th17 response.

Aim: To analyze a broad spectrum of cytokine in the serum of patients with JDM. Background: Juvenile dermatomyositis (JDM) is the most common subtype of idiopathic inflammatory myopathies characterized by muscle and skin involvement. The etiology of JDM is unclear. A variety of cytokines play a role in the pathogenesis of JDM. Interferons, galectin-9, CLCX10, and neopterin are the most promising biomarkers. Objective: This study describes the associations between clinical symptoms, cytokine, and interferon profiles in children with JDM. Materials and Methods: Ten patients (6 girls and 4 boys) with JDM were included in the study. The clinical symptoms, disease activity (CMAS, CAT), laboratory parameters, and treatment were assessed. Forty-one cytokines levels and IFN-I scores in the serum were measured. The levels of cytokines were compared with a group of healthy controls (n=25). Results: Significant differences were observed in 21 of 41 analyzed cytokines between JDM patients and healthy controls. Patients with active disease (n=8) have higher levels of fractalkine (p = 0.036), IFNa (p = 0.037), IFNg (p = 0.037), GRO (p = 0.037), IL-10 (p = 0.037), IL-12p40 (p = 0.037), IL-12p70 (p = 0.048), IL-17a (p = 0.048), IL-1RA (p = 0.037), IL-1a (p = 0.037), compared to patients with inactive disease (n=2). A strong positive association was found between aCAT activity and eotaxin (r=0.753, p =0.012), GRO (r=0.735, p =0.015), IP-10 (r=0.805, p =0.005), and MCP-1 (r=0.734, p =0.016). A strong negative correlation association was observed between CMAS and eotaxin (r= -0.714, p =0.020), GRO (r= -0.727, p =0.017), IL-10 (r= -0.786, p =0.007), IP-10 (r= - 0.719, p =0.019), and MCP-1 (r= -0.800, p =0.005). IFN-I scores showed a positive correlation with IFNa (r=0.790, p =0.007), GRO (r=0.736, p =0.015) and IL-1RA (r=0.930, p <0.001). Conclusion: Among the spectrum of 41 cytokines, GRO, eotaxin, IP-10, and MCP-1 have shown the strongest association with JDM activity.

Background: Necrotizing enterocolitis (NEC) is a common gastrointestinal emergency among neonates which is characterized by acute intestinal inflammation and necrosis. The main risk factors for NEC are prematurity, low birth weight, and some preexisting health conditions such as congenital heart defects (CHDs). Investigation of the potential genetic predisposition to NEC is a promising approach that might provide new insights into its pathogenesis. One of the most important proteins that play a significant role in the pathogenesis of NEC is Toll-like receptor 4 (TLR4) which recognizes lipopolysaccharide found in Gram-negative bacteria. In intestinal epithelial cells, a protein encoded by the SIGIRR gene is a major inhibitor of TLR4 signaling. A few SIGIRR variants, including rare p.Y168X and p.S80Y, have already been identified in preterm infants with NEC, but their pathogenic significance remains unclear. This study aimed to investigate the spectrum of SIGIRR genetic variants in term newborns with CHD and to assess their potential association with NEC. Methods and Results: A total of 93 term newborns with critical CHD were enrolled in this study, 33 of them developed NEC. SIGIRR genetic variants were determined by Sanger sequencing of all exons. In total, eight SIGIRR genetic variants were identified, two of which were found only in newborns with NEC (P = 0.12). The rare missense p.S80Y (rs117739035) variant in exon 4 was found in two infants with NEC stage IIA. Two infants with NEC stage III and stage IB carried a novel duplication c. 102_121dup (rs552367848) variant in exon 10 that has not been previously associated with any clinical phenotype. Conclusions: The presence of both variants only in neonates who developed NEC, together with earlier published data, may suggest their potential contribution to the risk of developing NEC in term infants with CHD and allow planning larger cohort studies to clarify their relevance.

COVID-19, caused by SARS-CoV-2, triggers a complex immune response, with T regulatory cells (Tregs) playing a crucial role in maintaining immune homeostasis and preventing excessive inflammation. The current study investigates the function of T regulatory cells during COVID-19 infection and the subsequent recovery period, emphasizing their impact on immune regulation and inflammation control. We conducted a comprehensive analysis of Treg subpopulations in peripheral blood samples from COVID-19 patients at different stages: acute infection, early convalescence, and long-term recovery. Flow cytometry was employed to quantify Tregs including “naïve”, central memory (CM), effector memory (EM), and terminally differentiated CD45RA+ effector cells (TEMRA). Additionally, the functional state of the Tregs was assessed by the expression of purinergic signaling molecules (CD39, CD73). Cytokine profiles were assessed through multiplex analysis. Our findings indicate a significant decrease in the number of Tregs during the acute phase of COVID-19, which correlates with heightened inflammatory markers and increased disease severity. Specifically, we found a decrease in the relative numbers of “naïve” and an increase in EM Tregs, as well as a decrease in the absolute numbers of “naïve” and CM Tregs. During the early convalescent period, the absolute counts of all Treg populations tended to increase, accompanied by a reduction in pro-inflammatory cytokines. Despite this, one year after recovery, the decreased subpopulations of regulatory T cells had not yet reached the levels observed in healthy donors. Finally, we observed the re-establishment of CD39 expression in all Treg subsets; however, there was no change in CD73 expression among Tregs. Understanding these immunological changes across different T regulatory subsets and adenosine signaling pathways offers important insights into the disease’s pathogenesis and provides a broader view of immune system dynamics during recovery.

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Necrotizing enterocolitis (NEC) is a life-threatening disease that predominantly affects very low birth weight preterm infants. Development of NEC in preterm infants is accompanied by high mortality. Surgical treatment of NEC can be complicated by short bowel syndrome, intestinal failure, parenteral nutrition-associated liver disease, and neurodevelopmental delay. Issues surrounding pathogenesis, prevention, and treatment of NEC remain unclear. This review summarizes data on prenatal risk factors for NEC, the role of pre-eclampsia, and intrauterine growth retardation in the pathogenesis of NEC. The role of hypoxia in NEC is discussed. Recent data on the role of the intestinal microbiome in the development of NEC, and features of the metabolome that can serve as potential biomarkers, are presented. The Pseudomonadota phylum is known to be associated with NEC in preterm neonates, and the role of other bacteria and their metabolites in NEC pathogenesis is also discussed. The most promising approaches for preventing and treating NEC are summarized.

Currently, multiple studies have indicated that CD8+ T lymphocytes play a role in causing damage to the exocrine glands through acinar injury in primary Sjögren's syndrome (pSS). The aim of this research was to assess the imbalance of circulating CD8+ T cell subsets. We analyzed blood samples from 34 pSS patients and 34 healthy individuals as controls. We used flow cytometry to enumerate CD8+ T cell maturation stages, using as markers CD62L, CD28, CD27, CD4, CD8, CD3, CD45RA and CD45. For immunophenotyping of 'polarized' CD8+ T cell subsets, we used the following monoclonal antibodies: CXCR5, CCR6, CXCR3 and CCR4. The findings revealed that both the relative and absolute numbers of 'naïve' CD8+ T cells were higher in pSS patients compared to the healthy volunteers. Conversely, the proportions of effector memory CD8+ T cells were notably lower. Furthermore, our data suggested that among patients with pSS, the levels of cytotoxic Tc1 CD8+ T cells were reduced, while the frequencies of regulatory cytokine-producing Tc2 and Tc17 CD8+ T cells were significantly elevated. Simultaneously, the Tc1 cell subsets displayed a negative correlation with immunoglobulin G, rheumatoid factor, the Schirmer test and unstimulated saliva flow. On the other hand, the Tc2 cell subsets exhibited a positive correlation with these parameters. In summary, our study indicated that immune dysfunction within CD8+ T cells, including alterations in Tc1 cells, plays a significant role in the development of pSS.

BACKGROUND:it has been suggested that chronic low-grade inflammation plays an important role in the pathogenesis of polycystic ovary syndrome (PCOS). According to previous studies, it remains unclear which cytokines influence the development of this syndrome and whether their increase is associated with the presence of excess weight/obesity or is an independent factor. The aim of our research was to determine the parameters of chronic inflammation in women with PCOS in comparison with healthy women in the normal weight and the overweight subgroups.METHODS:This case-control study included 44 patients with PCOS (19 women with a body mass index (BMI) < 25 kg/m² and 25 women with a BMI ≥ 25 kg/m²) and 45 women without symptoms of PCOS (22 women with a BMI < 25 kg/m² and 23 women with a BMI ≥ 25 kg/m²). Thirty-two cytokines were analyzed in the plasma of the participants using Immunology multiplex assay HCYTA-60K-PX48 (Merck Life Science, LLC, Germany).RESULTS:Cytokines: interleukin-1 receptor antagonist (IL-1 RA), IL-2, IL-6, IL-17 E, IL-17 A, IL-18, and macrophage inflammatory protein-1 alpha (MIP-1 α) were increased in women with PCOS compared to controls, both in lean and overweight/obese subgroups (p < 0.05). Moreover, only lean women with PCOS had higher levels of IL-1 alpha, IL-4, IL-9, IL-12, IL-13, IL-15, tumor necrosis factor (TNF- α) alpha and beta, soluble CD40 and its ligand (SCD40L), fractalkine (FKN), monocyte-chemotactic protein 3 (MCP-3), and MIP-1 β compared to the control group (p < 0.05). IL-22 was increased in the combined group of women with PCOS (lean and overweight/obese) compared to the control group (p = 0.012).CONCLUSION:Chronic low-grade inflammation is an independent factor affecting the occurrence of PCOS and does not depend on the presence of excess weight/obesity. For the first time, we obtained data on the increase in such inflammatory parameters as IL-9, MCP-3, and MIP-1α in women with PCOS.

Background. Polycystic ovary syndrome (PCOS) is the most common endocrine disorder affecting 10-15% of women of reproductive age. PCOS is often associated with metabolic disorders, type 2 diabetes, cardiovascular disease, and other complications. In recent years, angiogenesis has been widely discussed as an important factor in the pathogenesis of PCOS. Objective. To identify growth factors in women with PCOS compared with healthy women in normal and overweight subgroups. Design and methods. This case-control study carried out at the Almazov National Medical Research Centre (ANMRC) included 45 patients with PCOS (22 women with a body mass index (BMI) < 25 kg/m 2 and 23 women with a BMI > 25 kg/m 2 ) and 45 women with normal ovulation (22 women with a BMI < 25 kg/m 2 and 23 women with a BMI > 25 kg/m 2 ). Seven growth factors were analyzed in the plasma of patients. Results. Compared to the control group, normal weight women with PCOS had higher plasma levels of EGF (medians were 5.57 and 0 pg/ml, p = 0.040) and FLT3L (medians were 5.0 and 2.25 pg/ml, p = 0.018). Growth factors FGF 2 and TGF alpha were increased in women with PCOS both in overweight and normal weight subgroups (p<0.001). Conclusion. In both overweight and non-overweight groups, women with PCOS show an increase in growth factors.

BACKGROUND Necrotizing enterocolitis (NEC) is a multifactorial disease that predominantly affects premature neonates. Intestinal dysbiosis plays a critical role in NEC pathogenesis in premature neonates. The main risk factor for NEC in term infants is mesenteric hypoperfusion associated with ductal-dependent congenital heart disease (CHD) that eventually leads to intestinal ischemia. The incidence of NEC in neonates with critical CHD is 6.8%-13%. However, the role of the intestinal microbiome in NEC pathogenesis in infants with ductal-dependent CHD remains unclear. CASE SUMMARY A male term neonate with right atrial isomerism underwent modified Blalock-Taussig shunt placement on the 14th day of life and had persistent mesenteric hypoperfusion after surgery. The patient had episodes of NEC stage IIA on the 1st and 28th days after cardiac surgery. Fecal microbial composition was analyzed before and after cardiac surgery by sequencing region V4 of the 16S rRNA gene. Before surgery, species belonging to genera Veillonella and Clostridia and class Gammaproteobacteria were detected, Bifidobacteriaceae showed a low abundance. The first NEC episode was associated with postoperative hemodynamic instability, intestinal ischemia-reperfusion injury during cardiopulmonary bypass, and a high abundance of Clostridium paraputrificum (Clostridium sensu stricto I) (56.1%). Antibacterial therapy after the first NEC episode resulted in increased abundance of Gammaproteobacteria, decreased abundance of Firmicutes, and low alpha diversity. These changes in the microbial composition promoted the growth of Clostridium sensu stricto I (72.0%) before the second NEC episode. CONCLUSION A high abundance of Clostridium sensu stricto I and mesenteric hypoperfusion may have contributed to NEC in the present case.

Hypercytokinemia, found in SARS-CoV-2 infection, contributes to multiple organ dysfunctions with acute respiratory distress syndrome, shock etc. The aim of this study was to describe cytokine storm signatures in patients with acute COVID-19 and to investigate their influence on severity of the infection. Plasma levels of 47 cytokines were investigated in 73 patients with moderate and severe COVID-19 (41 and 32, respectively) and 11 healthy donors (HD). The most elevated levels comparing patients and the HD were observed for seven pro-inflammatory cytokines (IL-6, IL-8, IL-15, IL-18, IL-27, IFNγ, TNFα), three chemokines (GROα, IP-10, MIG), two anti-inflammatory cytokines (IL-1RA, IL-10), and two growth factors (G-CSF, M-CSF). The patients with severe disease had significantly higher levels of FGF-2/FGF-basic, IL-1β, and IL-7 compared to the HD. The two groups of patients differed from each other only based on the levels of EGF, eotaxin, and IL-12 p40. Pneumonia lung injury, characterized by computer tomography, positively correlated with levels of EGF, IP-10, MCP-3 levels and negatively with IL-12 p40. Pro-inflammatory factors including IL-6, TNFα, and IP-10 negatively correlated with the frequency of the circulating T-helper17-like cells (Th17-like) and follicular Th cells that are crucial to develop SARS-CoV-2-specific plasma cells and memory B cells. Obtained data on the cytokine levels illustrate their influence on progression and severity of COVID-19.

Background systemic lupus erythematosus (SLE) as “the disease of thousand faces” has multiple pathogenic mechanisms with disturbance in different parts of immune system. A variety of cytokines have been found as a biomarker of active disease and a candidate for targeting treatment [1]. Objectives to analyze 38 cytokines profile in juvenile SLE (jSLE) and compare them with disease activity and clinical manifestations. Methods 29 patients with SLE under 18 years (3 boys, 26 girls, median age – 16.0 (13.0; 16.9) and 28 health control patients (14 boys, 14 girls, median age 16.0 (11.0; 17.0) were included in the study. Cytokine levels in the serum were measured by multiplex analysis using the MILLIPLEX MAP Human Cytokine/Chemokine/Growth Factor Panel A 41 plex kit (MilliporeSigma, USA) on the Luminex MAGPIX System (Luminex, USA). Results significant differences between jSLE patients and health control have observed in 10 cytokines (Table 1). Interestingly upregulation in jSLE compared to HC was found only in IP10 and IL1RA, while other cytokines were lower. MCP1 was associated with disease activity measured by SLEDAI (p=0.0073), while activity measured by ECLAM correlated with TGFa (p=0.049), MCP3 (p=0.025), IL-15 (0.038), IL-7 (p=0.002), IL-8 (0.043), MCP1 (p=0.014), MIP1b (p=0.014). Positive correlation was found between skin involvement and IL-6 (p=0.43), carditis and FLT-3L (p=0.018), IL1RA (p=0.03), IL-8 (p=0.019), TNFa (p=0.05), lung involvement and FLT3-3L (p=0.014), IL-15 (p=0.047), IL1RA (p=0.034), IL-5 (p=0.005), TNFa (p=0.004), myositis and TGFa (p=0.011), MCP3 (p=0.000), IL-13 (p=0.000), IL1a (p=0.000), IL-9 (p=0.000), IL1b (p=0.03), IL-4 (p=0.000) TNFb (p=0.000), anti-dsDNA levels and MDC (p=0.016), anemia and GRO (p=0.030), IL-1b (p=0.050), IL-3 (p=0.022). There’s no correlation between nephritis, CNS involvement and cytokines levels. Table 1. Cytokines jSLE (n=29) HC (n=28) p-value EGF 28.4 (15.3-133.3) 122.0 (25.8-218.5) 0.032 TGFa 1.4 (0.0-2.6) 4.6 (3.2-7.7) 0.00001 IL-10 3.8 (2.8-8.7) 2.4 (2.0-3.6) 0.034 MDC 461.3 (297.8-663.3) 1042.5 (808.9-1277.5) 0.00000 sCD40L 945.6 (126.5-1322.0) 1991.5 (1275.0-2395.0) 0.00003 IL1RA 21.9 (12.3-38.7) 12.3 (8.6-19.4) 0.013 IL1b 0.9 (0.6-1.2) 1.0 (0.9-1.9) 0.010 IL4 17.3 (11.1-32.2) 35.2 (19.6-87.8) 0.003 IL5 1.0 (0.8-1.4) 1.6 (1.0-3.0) 0.038 IL8 9.1 (7.4-21.3) 30.1 (11.5-46.5) 0.010 IP10 310.9 (215.6-472.1) 118.0 (89.3-143.7) 0.000009 Conclusion we identified differences in cytokines levels between jSLE patients and HC and found multiple correlation between manifestations and different cytokines levels. Most of them were in FLT-3L, MIP-1b, TNFa, IL1RA, IL-3, IL-5, IL-8, IL-15, MCP1 and MCP3. References [1]Idborg H, Oke V. Cytokines as Biomarkers in Systemic Lupus Erythematosus: Value for Diagnosis and Drug Therapy. Int J Mol Sci. 2021;22(21):11327. Published 2021 Oct 20. doi:10.3390/ijms222111327 Acknowledgements This research was funded by the Ministry of Science and Higher Education of the Russian Federation (Agreement No. 075-15-2020-901) Disclosure of Interests None declared

Recent studies showed that a low 25-hydroxyvitamin D (25(OH)D) level was associated with a higher risk of morbidity and severe course of COVID-19. Our study aimed to evaluate the effects of cholecalciferol supplementation on the clinical features and inflammatory markers in patients with COVID-19. A serum 25(OH)D level was determined in 311 COVID-19 patients. Among them, 129 patients were then randomized into two groups with similar concomitant medication. Group I (n = 56) received a bolus of cholecalciferol at a dose of 50,000 IU on the first and the eighth days of hospitalization. Patients from Group II (n = 54) did not receive the supplementation. We found significant differences between groups with the preferential increase in serum 25(OH)D level and Δ 25(OH)D in Group I on the ninth day of hospitalization (p < 0.001). The serum 25(OH)D level on the ninth day was negatively associated with the number of bed days (r = −0.23, p = 0.006); we did not observe other clinical benefits in patients receiving an oral bolus of cholecalciferol. Moreover, in Group I, neutrophil and lymphocyte counts were significantly higher (p = 0.04; p = 0.02), while the C-reactive protein level was significantly lower on the ninth day of hospitalization (p = 0.02). Patients with supplementation of 100,000 IU of cholecalciferol, compared to those without supplementation, showed a decrease in the frequencies of CD38++CD27 transitional and CD27−CD38+ mature naive B cells (p = 0.006 and p = 0.02) and an increase in the level of CD27−CD38− DN B cells (p = 0.02). Thus, the rise in serum 25(OH)D level caused by vitamin D supplementation in vitamin D insufficient and deficient patients may positively affect immune status and hence the course of COVID-19.

A low 25-hydroxyvitamin D (25(OH)D) level is considered as an independent risk factor for COVID-19 severity. However, the association between vitamin D status and outcomes in COVID-19 is controversial. In the present study we investigate the association between the serum 25(OH)D level, immune response, and clinical disease course in patients with COVID-19. A total of 311 patients hospitalized with COVID-19 were enrolled. For patients with a vitamin D deficiency/insufficiency, the prevalence of severe COVID-19 was higher than in those with a normal 25(OH)D level (p < 0.001). The threshold of 25(OH)D level associated with mortality was 11.4 ng/mL (p = 0.003, ROC analysis). The frequency of CD3+CD4+ T helper (Th) cells was decreased in patients with 25(OH)D level ≤ 11.4 ng/mL, compared to healthy controls (HCs). There were no differences in the frequency of naive, central memory (CM), effector memory (EM), and terminally differentiated effector memory Th cells in patients with COVID-19 compared to HCs. The frequency of T-follicular helpers was decreased both in patients with 25(OH)D level > 11.4 ng/mL (p < 0.001) and 25(OH)D level ≤ 11.4 ng/mL (p = 0.003) compared to HCs. Patients with 25(OH)D level > 11.4 ng/mL had an increased frequency of Th2 CM (p = 0.010) and decreased Th17 CM (p < 0.001). While the frequency of Th2 EM was significantly increased, the frequency of Th17 EM was significantly decreased in both groups compared to HCs. Thus, 25(OH)D level is an independent risk factor for the disease severity and mortality in patients with COVID-19. We demonstrate that the serum 25(OH)D level ≤ 11.4 ng/mL is associated with the stimulation of Th2 and the downregulation of Th17 cell polarization of the adaptive immunity in patients with COVID-19.

Kaplina, A.; Zaikova, E.; Sitkin, S.; Ivanov, A.; Ulyantsev, V.; Pervunina, T.; Treskina, N.; Fedoseeva, T.; Kalinina, O.; Petrova, N. Author Information