Background A subset of patients with severe COVID-19 develop a hyperinflammatory syndrome, which might contribute to morbidity and mortality. This study explores a specific phenotype of COVID-19-associated hyperinflammation (COV-HI), and its associations with escalation of respiratory support and survival. Methods In this retrospective cohort study, we enrolled consecutive inpatients (aged ≥18 years) admitted to University College London Hospitals and Newcastle upon Tyne Hospitals in the UK with PCR-confirmed COVID-19 during the first wave of community-acquired infection. Demographic data, laboratory tests, and clinical status were recorded from the day of admission until death or discharge, with a minimum follow-up time of 28 days. We defined COV-HI as a C-reactive protein concentration greater than 150 mg/L or doubling within 24 h from greater than 50 mg/L, or a ferritin concentration greater than 1500 μg/L. Respiratory support was categorised as oxygen only, non-invasive ventilation, and intubation. Initial and repeated measures of hyperinflammation were evaluated in relation to the next-day risk of death or need for escalation of respiratory support (as a combined endpoint), using a multi-level logistic regression model. Findings We included 269 patients admitted to one of the study hospitals between March 1 and March 31, 2020, among whom 178 (66%) were eligible for escalation of respiratory support and 91 (34%) patients were not eligible. Of the whole cohort, 90 (33%) patients met the COV-HI criteria at admission. Despite having a younger median age and lower median Charlson Comorbidity Index scores, a higher proportion of patients with COV-HI on admission died during follow-up (36 [40%] of 90 patients) compared with the patients without COV-HI on admission (46 [26%] of 179). Among the 178 patients who were eligible for full respiratory support, 65 (37%) met the definition for COV-HI at admission, and 67 (74%) of the 90 patients whose respiratory care was escalated met the criteria by the day of escalation. Meeting the COV-HI criteria was significantly associated with the risk of next-day escalation of respiratory support or death (hazard ratio 2·24 [95% CI 1·62–2·87]) after adjustment for age, sex, and comorbidity. Interpretation Associations between elevated inflammatory markers, escalation of respiratory support, and survival in people with COVID-19 indicate the existence of a high-risk inflammatory phenotype. COV-HI might be useful to stratify patient groups in trial design. Funding None.

SummaryNon-alcoholic fatty liver disease (NAFLD) is a very common indication for liver transplantation. How fat-rich diets promote progression from fatty liver to more damaging inflammatory and fibrotic stages is poorly understood. Here, we show that disrupting phosphorylation at Ser196 (S196A) in the liver X receptor alpha (LXRα, NR1H3) retards NAFLD progression in mice on a high-fat-high-cholesterol diet. Mechanistically, this is explained by key histone acetylation (H3K27) and transcriptional changes in pro-fibrotic and pro-inflammatory genes. Furthermore, S196A-LXRα expression reveals the regulation of novel diet-specific LXRα-responsive genes, including the induction of Ces1f, implicated in the breakdown of hepatic lipids. This involves induced H3K27 acetylation and altered LXR and TBLR1 cofactor occupancy at the Ces1f gene in S196A fatty livers. Overall, impaired Ser196-LXRα phosphorylation acts as a novel nutritional molecular sensor that profoundly alters the hepatic H3K27 acetylome and transcriptome during NAFLD progression placing LXRα phosphorylation as an alternative anti-inflammatory or anti-fibrotic therapeutic target.

Objective Similarities in the clinical and laboratory features of primary Sjögren’s syndrome (SS) and systemic lupus erythematosus (SLE) have led to attempts to treat patients with primary SS or SLE with similar biologic therapeutics. However, the results of many clinical trials are disappointing, and no biologic treatments are licensed for use in primary SS, while only a few biologic agents are available to treat SLE patients whose disease has remained refractory to other treatments. With the aim of improving treatment selections, this study was undertaken to identify distinct immunologic signatures in patients with primary SS and patients with SLE, using a stratification approach based on immune cell endotypes. Methods Immunophentyping of 29 immune cell subsets was performed using flow cytometry in peripheral blood from patients with primary SS (n = 45), patients with SLE (n = 29), and patients with secondary SS associated with SLE (SLE/SS) (n = 14), all of whom were considered to have low disease activity or be in clinical remission, and sex‐matched healthy controls (n = 31). Data were analyzed using supervised machine learning (balanced random forest, sparse partial least squares discriminant analysis), logistic regression, and multiple t‐tests. Patients were stratified by K‐means clustering and clinical trajectory analysis. Results Patients with primary SS and patients with SLE had a similar immunologic architecture despite having different clinical presentations and prognoses. Stratification of the combined primary SS, SLE, and SLE/SS patient cohorts by K‐means cluster analysis revealed 2 endotypes, characterized by distinct immune cell profiles spanning the diagnoses. A signature of 8 T cell subsets that distinctly differentiated the 2 endotypes with high accuracy (area under the curve 0.9979) was identified in logistic regression and machine learning models. In clinical trajectory analyses, the change in damage scores and disease activity levels from baseline to 5 years differed between the 2 endotypes. Conclusion These findings identify an immune cell toolkit that may be useful for differentiating, with high accuracy, the immunologic profiles of patients with primary SS and patients with SLE as a way to achieve targeted therapeutic approaches.

Objectives Cardiovascular disease (CVD) is the leading cause of mortality in patients with systemic lupus erythematosus (lupus). Therefore, using diet to control blood lipid levels and modify CVD risk could be a promising therapeutic strategy to control disease symptoms. The primary objective of this study was to learn about lupus patient experiences with diet including their opinion on considering diet as a therapeutic option. The secondary objective was to obtain this information in a cost and time effective manner. Methods A lay summary and a 15 question diet-based online survey was publicly available for 3 weeks. Social media was used to promote the survey through relevant charities, hospitals and research groups. Results 300 responses were received, 284 of whom had lupus. Patients reported that there was a lack of clinical counselling regarding diet with only 24% of patients stating that their doctor had spoken to them about diet. Despite this, 100% of patients stated that they would change their diet if they knew it would help their symptoms and 83% would take part in a future diet-based clinical trial. Text analysis of patient research suggestions identified a particular interest in using diet to treat fatigue

The liver X receptor (LXR) is a key transcriptional regulator of cholesterol, fatty acid, and phospholipid metabolism. Dynamic remodeling of immunometabolic pathways, including lipid metabolism, is a crucial step in T cell activation. Here, we explored the role of LXR-regulated metabolic processes in primary human CD4+ T cells and their role in controlling plasma membrane lipids (glycosphingolipids and cholesterol), which strongly influence T cell immune signaling and function. Crucially, we identified the glycosphingolipid biosynthesis enzyme glucosylceramide synthase as a direct transcriptional LXR target. LXR activation by agonist GW3965 or endogenous oxysterol ligands significantly altered the glycosphingolipid:cholesterol balance in the plasma membrane by increasing glycosphingolipid levels and reducing cholesterol. Consequently, LXR activation lowered plasma membrane lipid order (stability), and an LXR antagonist could block this effect. LXR stimulation also reduced lipid order at the immune synapse and accelerated activation of proximal T cell signaling molecules. Ultimately, LXR activation dampened proinflammatory T cell function. Finally, compared with responder T cells, regulatory T cells had a distinct pattern of LXR target gene expression corresponding to reduced lipid order. This suggests LXR-driven lipid metabolism could contribute to functional specialization of these T cell subsets. Overall, we report a mode of action for LXR in T cells involving the regulation of glycosphingolipid and cholesterol metabolism and demonstrate its relevance in modulating T cell function.

Liver X Receptors (LXRs) are important transcriptional regulators of intracellular cholesterol, fatty acid, and phospholipid levels. LXRs can dampen inflammation in macrophages by promoting cholesterol efflux and altering plasma membrane lipid rafts; microdomains enriched for cholesterol and glycosphingolipids that regulate immune-cell signalling. However, little is known about the impact of LXR activators on T cell plasma membrane lipid rafts, which are critical for T-cell antigen receptor (TCR) signalling. Here we show that the LXR synthetic agonist GW3965 significantly increases glycosphingolipid levels and reduces cholesterol and lipid order (stability) in the plasma membrane of human CD4 + T cells. Moreover, the GSL biosynthesis enzyme UGCG was identified as a novel direct target of LXR activation. Importantly, LXR-mediated changes in T cell lipid composition were associated with altered spatiotemporal distribution of lipids and signalling molecules at the immune synapse. Crucially, LXR activation altered the kinetics of proximal TCR-signalling events in activated T cells, reduced T cell proliferation and enhanced the production of IL-2 and IL-4. Thus, LXR activation influences T cell function via alteration of the plasma membrane lipid profile. Finally, the expression of UGCG and other LXR-regulated genes and lipids was significantly dysregulated in T-cells isolated from people with multiple sclerosis. Overall, a novel action of LXR has been characterised that involves modulation of lipid raft-associated cholesterol and glycosphingolipids in CD4 + T-cells, which could be of therapeutic relevance in multiple sclerosis. Keywords liver X receptor -CD4 + T cell -lipid metabolismcholesterolglycosphingolipid-multiple sclerosis 3

SUMMARYUnderstanding the transition from fatty liver (steatosis) to inflammatory and fibrotic steatohepatitis, is key to define strategies that alter its progression. Here we show that, when challenged with a high fat-high cholesterol diet, mice carrying a mutation that abolishes phosphorylation at Ser196 (S196A) in the liver X receptor alpha (LXRα) exhibit reduced hepatic inflammation and fibrosis despite displaying enhanced steatosis. This is associated with a marked protection against cholesterol accumulation. Reduced steatohepatitis in S196A mice involves unique reprogramming of the liver transcriptome in response to the diet. Remarkably, impaired LXRα phosphorylation uncovers novel diet-specific/phosphorylation-sensitive genes, whose regulation does not simply mirror ligand-induced LXR activation. Regulation of these unique, dually responsive genes, is associated with the promotion of LXR and cofactor occupancy under a cholesterol-rich diet.Therefore, Ser196-LXRα phosphorylation acts as a novel nutritional sensor that triggers a unique diet-induced transcriptome, thereby modulating metabolic, inflammatory and fibrotic responses important in the transition to steatohepatitis.

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