TYPE I INTERFERON SCORE IS ASSOCIATED WITH THE SEVERITY AND POOR PROGNOSIS IN ANTI-MDA5 ANTIBODY-POSITIVE DERMATOMYOSITIS PATIENTS

BackgroundAnti-MDA5 antibody-positive dermatomyositis (anti-MDA5+DM) is a rare autoimmune disease associated with a high mortality rate due to rapid-progressive interstitial lung disease (RP-ILD), particularly in East Asia[1]. MDA5, acts as a cytoplasmic sensor of viral RNA, thus activating antiviral responses including the type I interferon (IFN) signaling pathway[2]. The involvement of type 1 IFN in the pathogenesis of MDA5+DM has been proposed based on the significantly elevated expression of its downstream stimulated genes(ISG) in muscle, skin, lung, and peripheral blood[3;4]. Janus kinase inhibitor, which targets the IFN pathway, combined with glucocorticoid could improve the survival of early-stage MDA5+DM-ILD patients[5]. In clinical practice, there is still an urgent demand for sensitive biomarkers to facilitate clinical risk assessment and precise treatment.ObjectivesThis study aimed to investigate the clinical significance of interferon score, especially IFN-I score, in patients with anti-MDA5+DM.MethodsDifferent subtypes of idiopathic inflammatory myopathy, including anti-MDA5+DM(n=61), anti-MDA5-DM(n=20), antisynthetase syndrome(ASS,n=22),polymyositis(PM,n=6) and immune-mediated necrotizing myopathy(IMNM,n=9), and 58 healthy controls were enrolled.. A multiplex quantitative real-time PCR(RT-qPCR) assay using four TaqMan probes was utilized to evaluate two type I ISGs (IFI44, MX1, which are used for IFN-I score), one type II ISG (IRF1), and one housekeeping gene (HRPT1). Clinical features and disease activity index were compared between high and low IFN-I score groups in 61 anti-MDA5+DM patients. The association between laboratory findings and the predictive value of baseline IFN-I score level for mortality was analyzed.ResultsThe IFN scores were significantly higher in patients with anti-MDA5+DM than in HC (Figure 1A). The IFN-I score correlated positively with serum IFN α(r = 0.335, P =0.008), ferritin (r = 0.302, P = 0.018), and Myositis Disease Activity Assessment Visual Analogue Scale (MYOACT) score(r=0.426, P=0.001). Compared with patients with low IFN-I scores, patients with high IFN-I scores showed increased MYOACT score, CRP, AST, ferritin, and the percentages of plasma cells (PC%) but decreased lymphocyte count, natural killer cell count, and monocyte count. The 3-month survival rate was significantly lower in patients with IFN-I score > 4.9 than in those with IFN-I score ≤ 4.9(72.9% vs. 100%, P=0.044)(Figure 1B).ConclusionIFN score, especially IFN-I score, detected by multiplex RT-qPCR, can be a valuable biomarker for monitoring disease activity and predicting mortality in anti-MDA5+DM patients.References[1]I.E. Lundberg, M. Fujimoto, J. Vencovsky, R. Aggarwal, M. Holmqvist, L. Christopher-Stine, A.L. Mammen, and F.W. Miller, Idiopathic inflammatory myopathies. Nat Rev Dis Primers 7 (2021) 86.[2]G. Liu, J.H. Lee, Z.M. Parker, D. Acharya, J.J. Chiang, M. van Gent, W. Riedl, M.E. Davis-Gardner, E. Wies, C. Chiang, and M.U. Gack, ISG15-dependent activation of the sensor MDA5 is antagonized by the SARS-CoV-2 papain-like protease to evade host innate immunity. Nat Microbiol 6 (2021) 467-478.[3]G.M. Moneta, D. Pires Marafon, E. Marasco, S. Rosina, M. Verardo, C. Fiorillo, C. Minetti, L. Bracci-Laudiero, A. Ravelli, F. De Benedetti, and R. Nicolai, Muscle Expression of Type I and Type II Interferons Is Increased in Juvenile Dermatomyositis and Related to Clinical and Histologic Features. Arthritis Rheumatol 71 (2019) 1011-1021.[4]Y. Ye, Z. Chen, S. Jiang, F. Jia, T. Li, X. Lu, J. Xue, X. Lian, J. Ma, P. Hao, L. Lu, S. Ye, N. Shen, C. Bao, Q. Fu, and X. Zhang, Single-cell profiling reveals distinct adaptive immune hallmarks in MDA5+ dermatomyositis with therapeutic implications. Nat Commun 13 (2022) 6458.[5]Z. Chen, X. Wang, and S. Ye, Tofacitinib in Amyopathic Dermatomyositis–Associated Interstitial Lung Disease. New England Journal of Medicine 381 (2019) 291-293.AcknowledgementsThis work was supported by the National Natural Science Foundation of China [81974251], and Shanghai Hospital Develop ent Center, Joint Research of New Advanced Technology Project [SHDC12018106]Disclosure of InterestsNone Declared.

Age-dependent NK cell dysfunctions in severe COVID-19 patients.

Natural Killer (NK) cells are key innate effectors of antiviral immune response, and their activity changes in ageing and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we investigated the age-related changes of NK cell phenotype and function during SARS-CoV-2 infection, by comparing adult and elderly patients both requiring mechanical ventilation. Adult patients had a reduced number of total NK cells, while elderly showed a peculiar skewing of NK cell subsets towards the CD56lowCD16high and CD56neg phenotypes, expressing activation markers and check-point inhibitory receptors. Although NK cell degranulation ability is significantly compromised in both cohorts, IFN-γ production is impaired only in adult patients in a TGF-ß-dependent manner. This inhibitory effect was associated with a shorter hospitalization time of adult patients suggesting a role for TGF-ß in preventing an excessive NK cell activation and systemic inflammation. Our data highlight an age-dependent role of NK cells in shaping SARS-CoV-2 infection toward a pathophysiological evolution.

Evaluation of the immunomodulatory effects of interleukin-10 on peripheral blood immune cells of COVID-19 patients: Implication for COVID-19 therapy.

Objective: Several therapies with immune-modulatory functions have been proposed to reduce the overwhelmed inflammation associated with COVID-19. Here we investigated the impact of IL-10 in COVID-19, through the ex-vivo assessment of the effects of exogenous IL-10 on SARS-CoV-2-specific-response using a whole-blood platform. Methods: Two cohorts were evaluated: in "study population A", plasma levels of 27 immune factors were measured by a multiplex (Luminex) assay in 39 hospitalized "COVID-19 patients" and 29 "NO COVID-19 controls" all unvaccinated. In "study population B", 29 COVID-19 patients and 30 NO COVID-19-Vaccinated Controls (NO COVID-19-VCs) were prospectively enrolled for the IL-10 study. Whole-blood was stimulated overnight with SARS-COV-2 antigens and then treated with IL-10. Plasma was collected and used for ELISA and multiplex assay. In parallel, whole-blood was stimulated and used for flow cytometry analysis. Results: Baseline levels of several immune factors, including IL-10, were significantly elevated in COVID-19 patients compared with NO COVID-19 subjects in "study population A". Among them, IL-2, FGF, IFN-γ, and MCP-1 reached their highest levels within the second week of infection and then decreased. To note that, MCP-1 levels remained significantly elevated compared with controls. IL-10, GM-CSF, and IL-6 increased later and showed an increasing trend over time. Moreover, exogenous addition of IL-10 significantly downregulated IFN-γ response and several other immune factors in both COVID-19 patients and NO COVID-19-VCs evaluated by ELISA and a multiplex analysis (Luminex) in "study population B". Importantly, IL-10 did not affect cell survival, but decreased the frequencies of T-cells producing IFN-γ, TNF-α, and IL-2 (p<0.05) and down-modulated HLA-DR expression on CD8+ and NK cells. Conclusion: This study provides important insights into immune modulating effects of IL-10 in COVID-19 and may provide valuable information regarding the further in vivo investigations.

Unraveling and targeting the innate immune response in Multisystem Inflammatory Syndrome in Children (MIS-C)

OBJECTIVES/GOALS: The innate immune responses to Multisystem Inflammatory Syndrome in Children (MIS-C) are not fully known. Using samples from MIS-C, we will assess the cellular responses and develop a novel Tri-Specific Killer Engager (TRiKE) that engages innate immune cells to improve those responses. METHODS/STUDY POPULATION: We collected blood samples from 60 pediatric patients from which we isolated plasma and peripheral blood mononuclear cells. We received blood samples from 13 MIS-C, 32 severe acute COVID, 5 COVID-19 asymptomatic, and 15 COVID-19 negative patients. Using plasma, we then performed ELISAs to determine IgG antibody levels against SARS-CoV-2 and plaque reduction neutralization tests to determine neutralizing antibody functions. We isolated DNA to look at Fc receptor genetics. We also utilized utilize flow cytometry assays determine the phagocytosis and killing abilities of the innate cells from these patients. This data will be correlated with clinical outcomes. Additionally, we have developed a novel SARS-CoV-2 TRiKE which directs natural killer (NK) cell killing specifically to of COVID-19 infected cells. RESULTS/ANTICIPATED RESULTS: MIS-C patients had higher IgG antibody titers against SARS-CoV-2 compared to children with symptomatic or asymptomatic COVID. MIS-C patients also neutralized SARS-CoV-2 more effectively than children with acute symptomatic or asymptomatic COVID-19. We found natural killer cells and monocytes are dysfunctional in MIS-C patients and do not kill SARS-CoV-2 infected cells as well. Specifically, NK cells do not kill COVID-19 infected cells as well. To combat this, we have successfully generated and are now testing a Tri-Specific Killer engager (TRiKE) which binds one ends to NK cells, one end to the Spike protein on COVID-19 infected cells and contains IL-15 to improve NK cell function. We anticipate that we can improve NK cell killing of COVID-19 infected cells with this TRiKE. DISCUSSION/SIGNIFICANCE: We found that MIS-C patients have antibodies that can neutralize SARS-CoV-2 but that that innate immune cells that engage antibodies are dysfunctional. We are have successfully developed and are targeting this response with a TRiKE to improve innate immune cell functional;this may serve as an adjunctive therapeutic if proven successful.

Characteristics and Potential Roles of Natural Killer Cells During SARS-CoV-2 Infection

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a tremendous burden on public health and world economies. An efficient host immune response to acute SARS-CoV-2 infection requires rapid and early activation of the innate immune system. Natural killer (NK) cells represent a critical component of the innate immunity. Here, the appearance of CD56-CD16+ NK cells and unconventional CD56dim CD16neg NK cells during the course of SARS-CoV-2 infection, and the phenotype and effector functions of NK cells during SARS-CoV-2 infection were summarized. The involvement of the dysregulated NK cells in the immunopathogenesis of the coronavirus disease 2019 (COVID-19) and clinical trials of adoptive NK cell-based therapies against COVID-19 were also discussed. © Wolters Kluwer Health, Inc. All rights reserved.

Natural killer (NK) cells: an innate defense shield against respiratory viral infections

In general, B and T lymphocytes, which are involved in adaptive immunity, are in charge of cell-mediated response and antibody-mediated immunity, respectively. Another subset of lymphocytes, known as natural killer (NK) cells, are innate effector cells. They serve as the body's initial line of defence against viral infections. They perform the task of eliminating stressed cells and are crucial for tumour immunity. These cells are capable of performing their killing function without clonal expansion and differentiation following activation. The NK cells will immediately eliminate infected host cells but other lymphocytes need lymphocyte proliferative response which takes several days and further differentiate into effector cells, so that they eliminate host cells infected by the viral pathogen. The NK cells also form a bridge between the adaptive and innate immunity and play significant roles during respiratory infection. Number and the role of NK cells correlate with the severity of severe acute respiratory syndrome (SARS);the number and the percentage of CD158b+ NK cells in severe SARS infection were significantly less in number than those with mild cases. Innate defence mechanisms, particularly NK cells, are able to control SARS infection even in the absence of T cells and antibodies, according to cellular immunological responses to SARS infection in mice. As a result, NK cells are crucial in the fight against viral infections of the respiratory system. As an innate immune system, they serve as the initial line of virus protection. It is possible to do additional research to take advantage of this NK cell trait and develop a cutting-edge therapeutic approach to fight developing respiratory viral diseases.

Chemokines and chemokine receptors during COVID-19 infection.

Chemokines are crucial inflammatory mediators needed during an immune response to clear pathogens. However, their excessive release is the main cause of hyperinflammation. In the recent COVID-19 outbreak, chemokines may be the direct cause of acute respiratory disease syndrome, a major complication leading to death in about 40% of severe cases. Several clinical investigations revealed that chemokines are directly involved in the different stages of SARS-CoV-2 infection. Here, we review the role of chemokines and their receptors in COVID-19 pathogenesis to better understand the disease immunopathology which may aid in developing possible therapeutic targets for the infection.

NK cells in COVID-19 - from disease to vaccination.

Natural killer (NK) cells participate in the host innate immune response to viral infection. Conversely, NK cell dysfunction and hyperactivation can contribute to tissue damage and immunopathology. Here, we review recent studies with respect to NK cell activity during infection with human severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Discussed are initial reports of patients hospitalized with coronavirus disease 2019 (COVID-19), which revealed prompt NK cell activation during the acute disease state. Another hallmark of COVID-19, early on observed, was a decrease in numbers of NK cells in the circulation. Data from patients with acute SARS-CoV-2 infection as well as from in vitro models demonstrated strong anti-SARS-CoV-2 activity by NK cells, likely through direct cytotoxicity as well as indirectly by secreting cytokines. Additionally, we describe the molecular mechanisms underlying NK cell recognition of SARS-CoV-2 infected cells, which involve triggering of multiple activating receptors including NKG2D as well as loss-of-inhibition through NKG2A. Discussed is also the ability of NK cells to respond to SARS-CoV-2 infection via antibody dependent cellular cytotoxicity. With the respect to NK cells in the pathogenesis of COVID-19, we review studies demonstrating how hyperactivation and misdirected NK cell responses could contribute to disease course. Finally, while knowledge is still rather limited, we discuss current insights suggesting a contribution of an early NK cell activation-response in the generation of immunity against SARS-CoV-2 following vaccination an anti-SARS-CoV-2 mRNA vaccines.

Comparison of T Lymphocyte Subsets and Natural Killer Lymphocytes in Moderate Versus Severe COVID-19 Patients.

Severe respiratory involvement that follows a process of immune dysregulation and intense cytokine production remains to be the most dreaded complication of Coronavirus Disease-2019 (COVID-19) infection. The aim of this study was to analyze T lymphocyte subsets and natural killer (NK) lymphocytes in moderate and severe cases of COVID-19 infection and assess their significance in disease severity and prognosis. Twenty moderate cases and 20 severe cases of COVID-19 were studied and compared regarding blood picture, biochemical markers, T lymphocyte population subsets, and NK lymphocytes, which were determined by flow cytometric analysis. On analyzing the flow cytometric data of T lymphocyte cells and their subsets and NK cells in two groups of COVID-19 infection (one group moderate and the other severe cases), some immature NK lymphocyte relative and absolute counts were higher in the severe patients with worse outcome and death, while some mature NK lymphocyte relative and absolute counts were depressed in both groups. Also, interleukin (IL)-6 was significantly higher in severe cases when compared to moderate cases, and there was a positive significant correlation between immature NK lymphocyte relative and absolute counts and IL-6. There was no statistically significant difference between T lymphocyte subsets (T helper and T cytotoxic) with disease severity or outcome. Some immature NK lymphocyte subsets contribute to the widespread inflammatory response that complicates severe cases of COVID-19; therapeutic approaches directed to enhancing NK maturation or drugs that block NK cell inhibitory receptors have a potential role in controlling COVID-19 induced cytokine storm.

Natural killer cells in sepsis: Friends or foes?

Sepsis is one of the major causes of death in the hospital worldwide. The pathology of sepsis is tightly associated with dysregulation of innate immune responses. The contribution of macrophages, neutrophils, and dendritic cells to sepsis is well documented, whereas the role of natural killer (NK) cells, which are critical innate lymphoid lineage cells, remains unclear. In some studies, the activation of NK cells has been reported as a risk factor leading to severe organ damage or death. In sharp contrast, some other studies revealed that triggering NK cell activity contributes to alleviating sepsis. In all, although there are several reports on NK cells in sepsis, whether they exert detrimental or protective effects remains unclear. Here, we will review the available experimental and clinical studies about the opposing roles of NK cells in sepsis, and we will discuss the prospects for NK cell-based immunotherapeutic strategies for sepsis.

Metabolism of NK cells during viral infections.

Cellular metabolism is essential for the correct function of immune system cells, including Natural Killer cells (NK). These cells depend on energy to carry out their effector functions, especially in the early stages of viral infection. NK cells participate in the innate immune response against viruses and tumors. Their main functions are cytotoxicity and cytokine production. Metabolic changes can impact intracellular signals, molecule production, secretion, and cell activation which is essential as the first line of immune defense. Metabolic variations in different immune cells in response to a tumor or pathogen infection have been described; however, little is known about NK cell metabolism in the context of viral infection. This review summarizes the activation-specific metabolic changes in NK cells, the immunometabolism of NK cells during early, late, and chronic antiviral responses, and the metabolic alterations in NK cells in SARS-CoV2 infection. The modulation points of these metabolic routes are also discussed to explore potential new immunotherapies against viral infections.

Case series evaluating lymphocyte subgroups at diagnosis and after treatment in multisystem inflammatory syndrome associated with COVID-19 in children

Objective: In this case series, we aimed to examine the changes in lymphocyte subgroups in children diagnosed with the multisystem inflammatory syndrome (MIS-C) during the acute phase and in the first month after treatment. Material and Methods: Ethics committee approval was received for the study from the Ethics Committee of Ondokuz Mayis University patient data were analyzed from medical records in an electronic database. Initial immunological evaluations of our first five patients diagnosed with MIS-C were made, steroid and IVIG treatments were given to the patients, and lymphocyte subgroups were evaluated for the second time in the first month for control purposes.

Siglec-9 Restrains Antibody-Dependent Natural Killer Cell Cytotoxicity against SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection alters the immunological profiles of natural killer (NK) cells. However, whether NK antiviral functions are impaired during severe coronavirus disease 2019 (COVID-19) and what host factors modulate these functions remain unclear. We found that NK cells from hospitalized COVID-19 patients degranulate less against SARS-CoV-2 antigen-expressing cells (in direct cytolytic and antibody-dependent cell cytotoxicity [ADCC] assays) than NK cells from mild COVID-19 patients or negative controls. The lower NK degranulation was associated with higher plasma levels of SARS-CoV-2 nucleocapsid antigen. Phenotypic and functional analyses showed that NK cells expressing the glyco-immune checkpoint Siglec-9 elicited higher ADCC than Siglec-9- NK cells. Consistently, Siglec-9+ NK cells exhibit an activated and mature phenotype with higher expression of CD16 (FcγRIII; mediator of ADCC), CD57 (maturation marker), and NKG2C (activating receptor), along with lower expression of the inhibitory receptor NKG2A, than Siglec-9- CD56dim NK cells. These data are consistent with the concept that the NK cell subpopulation expressing Siglec-9 is highly activated and cytotoxic. However, the Siglec-9 molecule itself is an inhibitory receptor that restrains NK cytotoxicity during cancer and other viral infections. Indeed, blocking Siglec-9 significantly enhanced the ADCC-mediated NK degranulation and lysis of SARS-CoV-2-antigen-positive target cells. These data support a model in which the Siglec-9+ CD56dim NK subpopulation is cytotoxic even while it is restrained by the inhibitory effects of Siglec-9. Alleviating the Siglec-9-mediated restriction on NK cytotoxicity may further improve NK immune surveillance and presents an opportunity to develop novel immunotherapeutic tools against SARS-CoV-2 infected cells. IMPORTANCE One mechanism that cancer cells use to evade natural killer cell immune surveillance is by expressing high levels of sialoglycans, which bind to Siglec-9, a glyco-immune checkpoint molecule on NK cells. This binding inhibits NK cell cytotoxicity. Several viruses, such as hepatitis B virus (HBV) and HIV, also use a similar mechanism to evade NK surveillance. We found that NK cells from SARS-CoV-2-hospitalized patients are less able to function against cells expressing SARS-CoV-2 Spike protein than NK cells from SARS-CoV-2 mild patients or uninfected controls. We also found that the cytotoxicity of the Siglec-9+ NK subpopulation is indeed restrained by the inhibitory nature of the Siglec-9 molecule and that blocking Siglec-9 can enhance the ability of NK cells to target cells expressing SARS-CoV-2 antigens. Our results suggest that a targetable glyco-immune checkpoint mechanism, Siglec-9/sialoglycan interaction, may contribute to the ability of SARS-CoV-2 to evade NK immune surveillance.

The role of the HLA allelic repertoire on the clinical severity of COVID-19 in Canadians, living in the Saskatchewan province.

AIMS: The HLA system has been implicated as an underlying determinant for modulating the immune response to SARS-CoV-2. In this study, we aimed to determine the association of patients' HLA genetic profiles with the disease severity of COVID-19 infection. METHODS: Prospective study was conducted on COVID-19 patients (n = 40) admitted to hospitals in Saskatoon, Canada, between March and December 2020. Next-generation sequencing was performed on the patient samples to obtain high-resolution HLA typing profiles. The statistical association between HLA allelic frequency and disease severity was examined. The disease severity was categorized based on the length of hospital stay and intensive care needs or demise during the hospital stay. RESULTS: HLA allelic frequencies of the high and low-severity cohorts were normalized against corresponding background allelic frequencies. In the high-severity cohort, A*02:06 (11.8-fold), B*51:01 (2.4-fold), B*15:01(3.1-fold), C*01:02 (3.3-fold), DRB1*08:02 (31.2-fold), DQ*06:09 (11-fold), and DPB1*04:02(4-fold) were significantly overrepresented (p < 0.05) making these deleterious alleles. In the low-severity cohort, A*24:02 (2.8-fold), B*35:01 (2.8-fold), DRB1*04:07 (5.3-fold), and DRB1*08:11 (22-fold) were found to be significantly overrepresented (p < 0.05) making these protective alleles. These above alleles interact with NK cell antiviral activity via the killer immunoglobulin-like receptors (KIR). The high-severity cohort had a higher predilection for HLA alleles associated with KIR subgroups; Bw4-80I (1.1-fold), and C1 (1.6-fold) which promotes NK cell inhibition, while the low-severity cohort had a higher predilection for Bw4-80T (1.6-fold), and C2 (1.6-fold) which promote NK cell activation. CONCLUSION: In this study, the HLA allelic repository with the distribution of deleterious and protective alleles was found to correlate with the severity of the clinical course in COVID-19. Moreover, the interaction of specific HLA alleles with the KIR-associated subfamily modulates the NK cell-mediated surveillance of SARS-CoV-2. Both deleterious HLA alleles and inhibitory KIR appear prominently in the severe COVID-19 group focusing on the importance of NK cells in the convalescence of COVID-19.

SARS-CoV-2 escapes direct NK cell killing through Nsp1-mediated downregulation of ligands for NKG2D.

Natural killer (NK) cells are cytotoxic effector cells that target and lyse virally infected cells; many viruses therefore encode mechanisms to escape such NK cell killing. Here, we interrogate the ability of SARS-CoV-2 to modulate NK cell recognition and lysis of infected cells. We find that NK cells exhibit poor cytotoxic responses against SARS-CoV-2-infected targets, preferentially killing uninfected bystander cells. We demonstrate that this escape is driven by downregulation of ligands for the activating receptor NKG2D (NKG2D-L). Indeed, early in viral infection, prior to NKG2D-L downregulation, NK cells are able to target and kill infected cells; however, this ability is lost as viral proteins are expressed. Finally, we find that SARS-CoV-2 non-structural protein 1 (Nsp1) mediates downregulation of NKG2D-L and that Nsp1 alone is sufficient to confer resistance to NK cell killing. Collectively, our work demonstrates that SARS-CoV-2 evades direct NK cell cytotoxicity and describes a mechanism by which this occurs.

Effect of Mg2+level on the functions of cd8+t lymphocytes and nk cells in patients with COVID-19

Objective:To investigate the changes of Mg2+ levels in serum and peripheral blood mononuclear cells (PB-MCs) of patients with COVID-19 and its effects on the functions of CD8+ T lymphocytes and NK cells.

Dynamic Evaluation of Natural Killer Cells Subpopulations in COVID-19 Patients.

The aim of the study was to evaluate the dynamic changes of the total Natural Killer (NK) cells and different NK subpopulations according to their differentiated expression of CD16/CD56 in COVID-19 patients. Blood samples with EDTA were analyzed on day 1 (admission moment), day 5, and day 10 for the NK subtypes. At least 30,000 singlets were collected for each sample and white blood cells were gated in CD45/SSC and CD16/CD56 dot plots of fresh human blood. From the lymphocyte singlets, the NK cells subpopulations were analyzed based on the differentiated expression of surface markers and classified as follows: CD16-CD56+/++/CD16+CD56++/CD16+CD56+/CD16++CD56-. By examining the CD56 versus CD16 flow cytometry dot plots, we found four distinct NK sub-populations. These NK subtypes correspond to different NK phenotypes from secretory to cytolytic ones. There was no difference between total NK percentage of different disease forms. However, the total numbers decreased significantly both in survivors and non-survivors. Additionally, for the CD16-CD56+/++ phenotype, we observed different patterns, gradually decreasing in survivors and gradually increasing in those with fatal outcomes. Despite no difference in the proportion of the CD16-CD56++ NK cells in survivors vs. non-survivors, the main cytokine producers gradually decline during the study period in the survival group, underling the importance of adequate IFN production during the early stage of SARS-CoV-2 infection. Persistency in the circulation of CD56++ NK cells may have prognostic value in patients, with a fatal outcome. Total NK cells and the CD16+CD56+ NK subtypes exhibit significant decreasing trends across the moments for both survivors and non-survivors.

OPPORTUNITIES FOR CORRECTION OF IMMUNOSUPPRESSION IN PATIENTS WITH COVID-19.

Here, we review thematic publications in available literature sources of the databases PubMed, Scopus, Web of Science, eLibrary, 49 of which were dated of the years 1997–2022. Analysis of such reports is aimed at assessing features of cytokine storm-induced hyperinflammatory reaction with signs of immunosuppression accompanied by pronounced lymphopenia and lowered count of CD4+T helpers during severe COVID-19. The prognostic factor for unfavorable prognosis was based on the marker of systemic inflammatory reaction correlating with the disease severity - the soluble IL-2 receptor as well as the neutrophil-to-lymphocyte ratio and the lymphocyte subset imbalance. An immunosuppressive therapy of severe forms of COVID-19, aimed at weakening the inflammatory response, exacerbates immune dysfunction by suppressing the T cell function, mainly due to Th1 lymphocytes involved in recognizing and eliminating intracellular pathogens particularly viruses. Upon that, cell-mediated immunity becomes compromised that relies on cytotoxic T-lymphocytes, natural killer cells and macrophages. Timely and targeted immunocorrection is required to prevent or reduce the immunosuppression that accompanies a severe disease course and leads to serious and prolonged complications, as well as to association of secondary infections. In fight against the cytokine storm, it is important not to miss a time point of developing immunosuppressive condition that transitions into immunoparalysis as follows from recent publications covering the tactics of treating immune-mediated complications of coronavirus infection. The review discusses opportunities for immunosuppressive therapy along with glucocorticosteroids and monoclonal antibodies blocking IL-6 or cognate receptors. Studies using mesenchymal stem cells (MSCs) to reduce systemic inflammatory response at COVID-19 are outlined in the review. The use of antigen-specific Treg and their combinations with antagonists of tumor necrosis factor-α (TNFα), interferon-γ (IFNγ) as well as low-dose IL-2 in patients with SARS-CoV-2 infection were analyzed. The prognostic perspectives for CAR-T cells and CAR-NK cells technology have been considered as novel therapeutic approaches aimed at “training” effector cells to recognize the surface SARS-CoV-2 virus spike-like (S) protein. The feasibility of a therapeutic approach is also emphasized by comparatively analyzed of efficacy of using IL-7 or IL-15 during lymphopenia in patients with COVID-19. Here, side effects complicating immunocorrection come to the fore. Critical evaluation of corrected immunosuppressive conditions in patients with COVID-19 in the post-COVID-19 period by using low-dose IL-2 therapy revealed its ability to repair cellular immune response. As a result, a low-dose IL-2 therapy is recommended as a cytokine replacement therapy in such patients with COVID-19 during hyper-to-hypo-inflammatory phase transition in immune response. (English) [ FROM AUTHOR] Обзор выполнен посредством поиска тематической информации среди доступных источников литературы в базах данных Pubmed, Scopus, Web of Science, eLibrary, 49 из которых (1997–2022 гг. издания) вошли в данный обзор. Анализ этих работ направлен на особенности индуцированной цитокиновым штормом гипервоспалительной реакции с признаками иммуносупрессии, сопровождающейся выраженной лимфопенией со снижением количества CD4+ Т-хелперов при тяжелом течении COVID-19. Прогностическим фактором неблагоприятного прогноза служит коррелирующий с тяжестью заболевания маркер системной воспалительной реакции - растворимый рецептор IL-2, а также соотношение нейтрофилов к лимфоцитам и дисбаланс субпопуляций лимфоцитов. Направленная на ослабление воспалительной реакции иммуносупрессивная терапия тяжелых форм COVID-19 усугубляет иммунную дисфункцию, подавляя Т-клеточный ответ, в основном, за счет Th1 лимфоцитов, участвующих в идентификации и элиминации внутриклеточных патогенов, в частности вирусов. При этом страдает клеточно-опосредованный иммунитет, который обеспечивают цитотоксические Т-лимфоциты, натуральные киллеры и макрофаги. Для предупреждения или ослабления иммуносупрессии, сопровождающей тяжелое течение и приводящей к серьезным и длительным осложнениям, а также к присоединению вторичных инфекций, необходима своевременная и адресная иммунокоррекция. Ð’ борьбе с цитокиновым штормом важно не упустить момент развития иммуносупрессивного состояния, переходящего в иммунопаралич, что следует из последних публикаций, освещающих тактику лечения иммуноопосредованных осложнений коронавирусной инфекции. Ð’ обзоре рассмотрены возможности иммуносупрессивной терапии, помимо глюкокортикостероидов и моноклональных антител, блокирующих IL-6 или его рецепторы. Приведены примеры работ с использованием мезенхимальных стволовых клеток (МСК) для снижения системной воспалительной реакции при COVID-19. Подвергнуто анализу применениеантиген-специфических Treg и их сочетаний с антагонистами фактора некроза опухолей α (TNFα), интерферона γ (IFNγ) и с низкими дозами IL-2 у пациентов с SARS-CoV-2-инфекцией. Прогностические перспективы технологии CAR-Т-клеток и CAR-NK-клеток рассмотрены в плане новых терапевтических подходов, нацеленных на «обучение» эффекторных ºÐ»ÐµÑ‚ок распознавать поверхностный шиповидный (S) белок вируса SARS-CoV-2. Целесообразностьиммунокоррегирующей терапии подчеркивается также сравнительным анализом эффективности IL-7 или IL-15 у пациентов с COVID-19 с иммуносупрессией. Критическая оценка коррекции иммуносупрессивных состояний у пациентов с COVID-19 в постковидный период с помощью низкодозной терапии препаратами IL-2 позволила выявить ее способность восстанавливать клеточный иммунный ответ. Ð’ результате в качестве заместительной цитокиновой терапии у этих пациентов, при переходе от гипервоспалительной к гиповоспалительной фазе иммунного ответа, может быть рекомендована низкодозная IL-2 терапия. (Russian) [ FROM AUTHOR] Copyright of Russian Journal of Infection & Immunity is the property of National Electronic-Information Consortium and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Assessment of Association Between the Potential Immunomodulatory Activity and Drinking Olive Leaf Tea in the Coronavirus Disease-2019 Pandemic: An Observational Study.

Objective: During the Coronavirus Disease-2019 (COVID-19) pandemic, in addition to the current measures, the healthy immune system plays an essential role and various natural agents have been recommended to boost innate immunity. The aim of this study was to investigate any association between the potential immunomodulatory activity and drinking olive leaf tea (OLT) in the COVID-19 pandemic. Design: The study was conducted among the workers in a tractor factory where OLT was served in routine. Drinking at least one cup of OLT per day for a minimum of 1 month was the inclusion criteria used in the study. The workers who had a history of vaccination and COVID-19 were excluded from the study, and lymphocyte subsets, interleukin (IL)-2, IFN-γ, COVID-19-specific IgM and IgG levels were analyzed in all the participants to determine the asymptomatic individuals among the participants and compare the immunological parameters. Results: The study was conducted among 336 workers, 183 of them were OLT drinkers and 153 were OLT nondrinkers. The results showed higher values of CD3-/CD16/56 (natural killer [NK]) cells, CD3+/CD16/56 (natural killer T [NKT]) cells, total NK (NK+NKT) cells, and serum IFN-γ, and IL-2 levels in OLT drinkers compared to the nondrinkers. Although all the OLT drinkers and nondrinkers included in the study reported no history of COVID-19, specific COVID-19 IgG levels were found positive in 60% of OLT drinkers and 38% OLT nondrinkers. Conclusions: Peripheral NK and NKT cell values and IL-2 and IFN-γ secretion levels were found higher in the OLT drinking group. There were positive correlations between the OLT drinking frequency and NK cell counts. Moreover, the number of individuals who had "asymptomatic" COVID-19 infection was higher in the OLT drinking group than in the nondrinking cohort. Clinical Trail: The trial has been registered in the ClinicalTrials.gov database (CTR NCT05222347).