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Overproduction of inflammatory cytokines is a keystone event in COVID-19 pathogenesis; TNF and its receptors (TNFR1 and TNFR2) are critical pro-inflammatory molecules. ADAM17 releases the soluble (sol) forms of TNF, TNFR1, and TNFR2. This study evaluated TNF, TNFRs, and ADAM17 at the protein, transcriptional, and gene levels in COVID-19 patients with different levels of disease severity. In total, 102 patients were divided into mild, moderate, and severe condition groups. A group of healthy donors (HD; n = 25) was included. Our data showed that solTNFR1 and solTNFR2 were elevated among the COVID-19 patients (p < 0.0001), without increasing the transcriptional level. Only solTNFR1 was higher in the severe group as compared to the mildly ill (p < 0.01), and the level was higher in COVID-19 patients who died than those that survived (p < 0.0001). The solTNFR1 level had a discrete negative correlation with C-reactive protein (p = 0.006, Rho = −0.33). The solADAM17 level was higher in severe as compared to mild disease conditions (p < 0.01), as well as in COVID-19 patients who died as compared to those that survived (p < 0.001). Additionally, a potential association between polymorphism TNFRSF1A:rs767455 and a severe degree of disease was suggested. These data suggest that solTNFR1 and solADAM17 are increased in severe conditions. solTNFR1 should be considered a potential target in the development of new therapeutic options.

Background: COVID-19 is an infectious disease caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Many COVID-19 patients require invasive mechanical ventilation (IMV) while others, even with acute respiratory failure, do not (NIMV). Therefore, we aimed to evaluate serum levels of MMP-7 and molecules related to exhausted T-cells as potential biomarkers to differentiate between IMV and NIMV patients. Methods: 105 patients diagnosed with COVID-19 and confirmed by RT-PCR for SARS-CoV-2 were divided into two groups according to the requirement for IMV. Serum levels of sPD-L1, sPD-L2, sTIM-3, sGal-9 and sMMP-7 were quantified by ELISA and correlated with clinical data. Twelve patients were followed up after eight months to compare the levels of the biomarkers between acute disease and post-COVID-19. Results: IMV patients experienced a lower PaO2/FiO2 (p < 0.0001) and a longer hospital stay (p < 0.0001), and exhibited higher levels of sPD-L1 (p < 0.05), sTIM-3 (p < 0.01) and sMMP-7 (p < 0.0001) when compared with NIMV patients. According to a ROC analysis, sMMP-7 had the highest sensitivity (78%) and specificity (76%) with a cut point of 4.5 ng/mL, followed by sTIM-3 and sPD-L1. Eight months post-COVID-19, IMV patients displayed a significant decrease in the initially high levels of sPD-L1, sTIM-3 and sGal-9, while sPD-L2 was increased, and sMMP-7 was unchanged. Conclusion: Circulating levels of sPD-L1, sTIM-3 and sMMP-7 are potential biomarkers of disease severity to distinguish patients requiring IMV. MMP-7 could also be a marker for the persistence of lung lesions post-COVID-19.

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Telomeres are localized at the end of chromosomes to provide genome stability; however, the telomere length tends to be shortened with each cell division inducing a progressive telomere shortening (TS). In addition to age, other factors, such as exposure to pollutants, diet, stress, and disruptions in the shelterin protein complex or genes associated with telomerase induce TS. This phenomenon favors cellular senescence and genotoxic stress, which increases the risk of the development and progression of lung diseases such as idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, SARS-CoV-2 infection, and lung cancer. In an infectious environment, immune cells that exhibit TS are associated with severe lymphopenia and death, whereas in a noninfectious context, naïve T cells that exhibit TS are related to cancer progression and enhanced inflammatory processes. In this review, we discuss how TS modifies the function of the immune system cells, making them inefficient in maintaining homeostasis in the lung. Finally, we discuss the advances in drug and gene therapy for lung diseases where TS could be used as a target for future treatments.

BackgroundRheumatoid arthritis–associated interstitial lung disease (RA-ILD) and idiopathic pulmonary fibrosis (IPF) share phenotypic similarities. The gain-of-function MUC5B promoter variant rs35705950 is the strongest risk factor for development of IPFObjectivesWe hypothesised that rs35705950 would also contribute to the risk of ILD in RA patients.MethodsUsing a French discovery population and multi-ethnic validation populations from 6 different countries, we tested the association of the MUC5B promoter variant in RA-ILD (n=620), RA without ILD (n=614), and unaffected controls (n=5448).ResultsThe discovery population revealed an association of the MUC5B promoter variant with RA-ILD when compared to unaffected controls (ORadj=3.8 95% CI: 2.8 to 5.2; p=9.7x10–17) (figure 1A). Similar to the discovery cohort, the MUC5B promoter variant was significantly over-represented among the cases of RA-ILD in the multi-ethnic study cohorts when compared to unaffected controls (OR adj=5.5 95% CI: 4.2 to 7.2; p=4.7x10–35) (figure 1A), and when the discovery population and the multi-ethnic cohorts were combined (OR combined=4.7 95% CI: 3.9 to 5.8; p=1.3x10–49) (figure 1A). Additionally, the MUC5B promoter variant was found to increase the risk of ILD among patients with RA (OR combined=3.1 95% CI: 1.8 to 5.4; p=7.4x10–5), however, no statistical association with the MUC5B promoter variant was observed for RA without ILD (figure 1B). The association of the MUC5B promoter variant with RA-ILD increased significantly when restricted to the usual interstitial pneumonia (UIP) by high-resolution computed tomography (OR combined=6.1 95% CI: 2.9 to 13.1; p=2.5x10–6) (figure 1C). Immunohistochemical and in-situ hybridization analysis of RA-ILD lung tissue demonstrated expression of MUC5B by type 2 alveolar epithelial cells undergoing endoplasmic reticulum stress.ConclusionsOur findings demonstrate that MUC5B promoter variant rs35705950 is a risk factor for RA-ILD specifically associated with radiologic evidence of UIP.Disclosure of InterestNone declared

BackgroundInterstitial lung abnormalities (ILA) occur in around 10% of subjects over 60 years, and are associated with a higher rate of all-cause mortality. The pathogenic mechanisms are unclear, and the putative contribution of alterations in the immune response has not been explored. Normal ageing is associated with immune deficiencies, including Naïve T-cell decrease and greater expression of the proliferative-limiting, co-inhibitory receptor killer-cell lectin-like receptor G1 (KLRG1).ObjectiveTo evaluate the frequency and activation state of different T-cell subpopulations in ILA subjects.MethodsPeripheral blood mononuclear cells were obtained from 15 individuals with ILA, 21 age-matched controls and 28 healthy young subjects. T-cells phenotype was characterised by flow cytometry, and proliferation and activation by stimulation with anti-CD3/anti-CD28 or phorbol myristate acetate/ionomycin; KLRG1 isoforms were evaluated by western blot and cytokines were quantified by ELISA and Multiplex.ResultsA significant increase of Naïve CD4+T cells together with a decrease of central and effector memory CD4+T cells was observed in ILA compared with age-matched controls. CD4+T cells from ILA subjects exhibited greater basal proliferation, which raised after anti-CD3/anti-CD28 stimulation. Additionally, a significant increase in the levels of interleukin-6 and interferon gamma was observed in isolated CD4+T cells and plasma of ILA subjects. They also displayed fewer KLRG1+/CD4+T cells with an increase of circulating E-cadherin, the ligand of KLRG1+. No changes were observed with CD8+T cell subsets.ConclusionCD4+T cells from ILA subjects are highly proliferative and show an excessive functional activity, likely related to the loss of KLRG1 expression, which may contribute to an inflammatory state and the development of ILA.