Search

COVID-19, caused by SARS-CoV-2, requires new approaches to control the disease. Programmed cell death protein (PD-1) and cytotoxic T-lymphocyte–associated protein 4 (CTLA4) play important roles in T-cell exhaustion in severe COVID-19. This study evaluated the frequency of whole blood lymphocytes expressing PD-1 and CTLA-4 in COVID-19 patients upon admission to the intensive care unit (ICU) (i.e., severe) or infection ward (i.e., moderate) and after 7 days of antiviral therapy. COVID-19 patients were treated with either favipiravir or Kaletra (FK group, 11 severe and 11 moderate) or dexamethasone plus remdesivir (DR group, 7 severe and 10 moderate) for 7 days in a pilot study. Eight healthy control subjects were also enrolled. The frequency of PD-1 + and CTLA4 + lymphocytes in whole blood was evaluated by flow cytometry. Patients on DR therapy had shorter hospital stays than those on FK therapy. The frequency of PD-1 + lymphocytes in the FK group at baseline differed between COVID-19 patients and healthy controls, while the frequency of both PD-1 + and CTLA-4 + cells increased significantly 7 days of FK therapy. The response was similar in both moderate and severe patients. In contrast, the frequency of PD-1 + and CTLA-4 + lymphocytes varied significantly between patients and healthy controls before DR treatment. DR therapy enhanced PD-1 + but not the CTLA-4 + frequency of these cells after 7 days. We show that the frequency of PD-1 and CTAL-4-bearing lymphocytes during hospitalization was increased in Iranian ICU COVID-19 patients who received FK treatment, but that the frequency of CTLA-4 + cells was higher at baseline and did not increase in patients who received DR. The effectiveness of DR treatment may reflect differences in T-cell activation or exhaustion status, particularly in CTLA-4-expressing cells. [ABSTRACT FROM AUTHOR]

The pathogenesis of coronavirus disease 2019 (COVID-19) is not fully elucidated. COVID-19 is due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which causes severe illness and death in some people by causing immune dysregulation and blood T cell depletion. Increased numbers of myeloid-derived suppressor cells (MDSCs) play a diverse role in the pathogenesis of many infections and cancers but their function in COVID-19 remains unclear. To evaluate the function of MDSCs in relation with the severity of COVID-19. 26 PCR-confirmed COVID-19 patients including 12 moderate and 14 severe patients along with 11 healthy age- and sex-matched controls were enrolled. 10 ml whole blood was harvested for cell isolation, immunophenotyping and stimulation. The immunophenotype of MDSCs by flow cytometry and T cells proliferation in the presence of MDSCs was evaluated. Serum TGF-β was assessed by ELISA. High percentages of M-MDSCs in males and of P-MDSCs in female patients were found in severe and moderate affected patients. Isolated MDSCs of COVID-19 patients suppressed the proliferation and intracellular levels of IFN-γ in T cells despite significant suppression of T regulatory cells but up-regulation of precursor regulatory T cells. Serum analysis shows increased levels of TGF-β in severe patients compared to moderate and control subjects (HC) (P = 0.003, P < 0.0001, respectively). The frequency of MDSCs in blood shows higher frequency among both moderate and severe patients and may be considered as a predictive factor for disease severity. MDSCs may suppress T cell proliferation by releasing TGF-β. [ABSTRACT FROM AUTHOR]

In this study, we first tried to determine whether the expression level of 9 miRNAs in the peripheral blood CD8+ T cells of asthmatic patients varies from that of controls, and secondly, we investigated the effects of fluticasone furoate and vilanterol on the expression level of these miRNAs. Fifteen subjects including 8 healthy individuals and 7 asthmatic patients were included in this study. CD8+T cells were isolated from participants' peripheral blood by a negative selection method using magnetic-activated cell sorting (MACS). The expression of 9 miRNAs was examined between the healthy individuals and asthmatic patients. Then the expression level of 9 miRNAs before and after treatment with the drugs was examined by quantitative real-time PCR. No significant changes in the expression level of 9 miRNAs were observed in asthmatic patients compared to the healthy controls. Fluticasone and vilanterol, in combination, had the greatest effect on miRNA expression. MiR-150 and miR-106a were the most and the least miRNAs, respectively, present in CD8+ T cells of patients and controls. MiR-106a and miR-126 had a positive correlation in CD8+ cells of asthmatic patients. Although no significant difference in the expression level of studies miRNAs was observed, the correlations among miRNAs were significant. Therefore, we suggest that the correlation between miRNAs would be a very important factor in physiological and pathological conditions in healthy individuals and asthmatic patients. Such a miRNA-miRNA correlation network can be even more critical than any changes in the variation of their expression in the CD8+ T cells. [ABSTRACT FROM AUTHOR]

The multifunctional role of mast cells (MCs) in the immune system is complex and has not fully been explored. MCs reside in tissues and mucous membranes such as the lung, digestive tract, and skin which are strategically located at interfaces with the external environment. These cells, therefore, will encounter external stimuli and pathogens. MCs modulate both the innate and the adaptive immune response in inflammatory disorders including transplantation. MCs can have pro- and anti-inflammatory functions, thereby regulating the outcome of lung transplantation through secretion of mediators that allow interaction with other cell types, particularly innate lymphoid cells (ILC2). ILC2 cells are a unique population of hematopoietic cells that coordinate the innate immune response against a variety of threats including infection, tissue damage, and homeostatic disruption. In addition, MCs can modulate alloreactive T cell responses or assist in T regulatory (Treg) cell activity. This paper outlines the current understanding of the role of MCs in lung transplantation, with a specific focus on their interaction with ILC2 cells within the engrafted organ. [ABSTRACT FROM AUTHOR]

Different phenotypes of asthma from mild to severe are categorized based on diverse clinical features. A guideline for the recognition and treatment of asthma has been provided by Global Initiative for Asthma (GINA). To control symptoms and prevent asthma exacerbation in most patients combinational therapy with inhaled corticosteroids (ICS) and a long acting B2-adrenreceptor agonist (LABA) are recommended. Understanding asthma phenotypes would be helpful to improve asthma diagnosis and treatment. The aim of this study was to verify glucocorticoid receptor glcococorticoid receptor (GR) nuclear translocation in CD4 T cells treated with fluticasone furoate (FF), vilanterol (V) and FF/V combination in severe asthmatic patients compare to patients with moderate asthma and healthy controls using Immunocytochemistry (ICC). After taking blood and separating PBMCs from each subject, CD4 T cells were isolated from PBMCs using CD4+ T cell isolation kit. Isolated CD4 T cells were cultured in presence of FF, V and FF/V combination for 1 hour and after cytocentrifugation, cells were incubated with anti GR-antibody and subsequently stained with FITC bound secondary antibody and GR nuclear translocation was observed under microscope. The results showed significant increasing in GR nuclear translocation in treated CD4 T cells from patients with moderate asthma and controls compare to those severe asthmatic patients, along with treating cells with FF/V combination no significant GR nuclear translocation was observed compare to that of using mono treatment of cells with FF and V. Based on our findings, it can be concluded different mechanisms are responsible for severe asthma and moderate asthma. [ABSTRACT FROM AUTHOR]

Background: Dendritic cells (DCs) as professional antigen presenting cells (APCs) play a critical role in the regulation of host immune responses. DCs evolve from immature, antigen-capturing cells, to mature antigen-presenting cells. The relative contribution of DCs to cigarette smoke-induced inflammation is not well documented. In the current study, we investigated a modulatory effect of cigarette smoke extract (CSE) on differentiation, maturation and function of DCs.Methods: Primary murine DCs were grown from bone marrow cells with GM-CSF. Development of DC was analyzed by expression of CD11c, MHCII, CD86, CD40 and CD83 using flow cytometry. Murine DC's and human L428 cells were co-cultured with CSE for various periods of time. Functional activity was analyzed by measuring FITC-dextran uptake, cytokine production and the ability to stimulate T cell activation in a mixed lymphocyte reaction.Results: Our results show that short-term CSE stimulation (~24 h) influence the maturation status of newly differentiated and immature DCs towards more mature cells as revealed by upregulation of MHCII, CD83, CD86, CD40, reduction in antigen up-take capacity and enhanced secretion of pro-inflammatory (IL-12, IL-6 and TNF-α) cytokines. Interestingly, long-term CSE exposure, time- and concentration-dependently, suppressed the development of functional DCs. This suppression was demonstrated by a decline in CD11c/MHCII, CD83, CD86 and CD40 expression, the production of cytokines and ability to stimulate T lymphocytes. Moreover, CSE significantly suppressed the endocytosis function of mouse DCs which was not due to diminished DC viability. Similar to mouse DCs, long-term co-culturing of the human L428 DC cell line with CSE time-dependently suppressed the expression of CD54.Conclusions: The present study provides evidence that CSE modulates DC-mediated immune responses via affecting both the function and maturation of DCs. The suppressive effects of cigarette smoke on DC function might lead to impaired immune responses to various infections. [ABSTRACT FROM AUTHOR]

Signaling by toll-like receptors (TLRs) initiates important immune responses against viral infection. The role of TLRs in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is not well elucidated. Thus, we investigated the interaction of TLRs agonists and SARS-COV-2 antigens with immune cells in vitro. 30 coronavirus disease 2019 (COVID-19) patients (15 severe and 15 moderate) and 10 age and sex-matched healthy control (HC) were enrolled. Peripheral blood mononuclear cells (PBMCs) were isolated and activated with TLR3, 7, 8, and 9 agonists, the spike protein (SP) of SARS-CoV-2, and the receptor binding domain (RBD) of SP. Frequencies of CD3+IFN-β+ T cells, and CD3+IFN-γ+ T cells were evaluated by flow cytometry. Interferon (IFN)-β gene expression was assessed by qRT-PCR. The frequency of CD3+IFN-β+ T cells was higher in PBMCs from moderate (p < 0.0001) and severe (p = 0.009) patients at baseline in comparison with HCs. The highest increase in the frequency of CD3+IFN-β+ T cells in cell from moderate patients was induced by TLR8 agonist and SP (p < 0.0001 for both) when compared to HC, while, the highest increase of the frequency of CD3+IFN-β+ T cells in sample of severe patients was seen with TLR8 and TLR7 agonists (both p = 0.002). The frequency of CD3+IFN-γ+ T cells was significantly increased upon stimulation with TLR agonists in cell from patients with moderate and severe COVID-19, compared with HC (all p < 0.01), except with TLR7 and TLR8 agonists. The TLR8 agonist did not significantly increase the frequency of CD3+IFN-γ+ T cells in PBMCs of severe patients, but did so in cells from patients with moderate disease (p = 0.01). Moreover, IFN-β gene expression was significantly upregulated in CD3+T cells from moderate (p < 0.0001) and severe (p = 0.002) COVID-19 patients, compared to HC after stimulation with the TLR8 agonist, while, stimulation of T cells with SP, significantly up-regulated IFN-β mRNA expression in cells from patients with moderate (p = 0.0003), but not severe disease. Stimulation of PBMCs from COVID-19 patients, especially patients with moderate disease, with TLR8 agonist and SP increased the frequency of IFN-β-producing T cells and IFN-β gene expression. [Display omitted] [ABSTRACT FROM AUTHOR]