Automated and reproducible cell identification in mass cytometry using neural networks.

The principal use of mass cytometry is to identify distinct cell types and changes in their composition, phenotype and function in different samples and conditions. Combining data from different studies has the potential to increase the power of these discoveries in diverse fields such as immunology, oncology and infection. However, current tools are lacking in scalable, reproducible and automated methods to integrate and study data sets from mass cytometry that often use heterogenous approaches to study similar samples. To address these limitations, we present two novel developments: (1) a pre-trained cell identification model named Immunopred that allows automated identification of immune cells without user-defined prior knowledge of expected cell types and (2) a fully automated cytometry meta-analysis pipeline built around Immunopred. We evaluated this pipeline on six COVID-19 study data sets comprising 270 unique samples and uncovered novel significant phenotypic changes in the wider immune landscape of COVID-19 that were not identified when each study was analyzed individually. Applied widely, our approach will support the discovery of novel findings in research areas where cytometry data sets are available for integration.

A global action agenda for turning the tide on fatty liver disease.

BACKGROUND AND AIMS: Fatty liver disease is a major public health threat due to its very high prevalence and related morbidity and mortality. Focused and dedicated interventions are urgently needed to target disease prevention, treatment, and care. APPROACH AND RESULTS: We developed an aligned, prioritized action agenda for the global fatty liver disease community of practice. Following a Delphi methodology over 2 rounds, a large panel (R1 n = 344, R2 n = 288) reviewed the action priorities using Qualtrics XM, indicating agreement using a 4-point Likert-scale and providing written feedback. Priorities were revised between rounds, and in R2, panelists also ranked the priorities within 6 domains: epidemiology, treatment and care, models of care, education and awareness, patient and community perspectives, and leadership and public health policy. The consensus fatty liver disease action agenda encompasses 29 priorities. In R2, the mean percentage of "agree" responses was 82.4%, with all individual priorities having at least a super-majority of agreement (> 66.7% "agree"). The highest-ranked action priorities included collaboration between liver specialists and primary care doctors on early diagnosis, action to address the needs of people living with multiple morbidities, and the incorporation of fatty liver disease into relevant non-communicable disease strategies and guidance. CONCLUSIONS: This consensus-driven multidisciplinary fatty liver disease action agenda developed by care providers, clinical researchers, and public health and policy experts provides a path to reduce the prevalence of fatty liver disease and improve health outcomes. To implement this agenda, concerted efforts will be needed at the global, regional, and national levels.

A global research priority agenda to advance public health responses to fatty liver disease.

BACKGROUND & AIMS: An estimated 38% of adults worldwide have non-alcoholic fatty liver disease (NAFLD). From individual impacts to widespread public health and economic consequences, the implications of this disease are profound. This study aimed to develop an aligned, prioritised fatty liver disease research agenda for the global health community. METHODS: Nine co-chairs drafted initial research priorities, subsequently reviewed by 40 core authors and debated during a three-day in-person meeting. Following a Delphi methodology, over two rounds, a large panel (R1 n = 344, R2 n = 288) reviewed the priorities, via Qualtrics XM, indicating agreement using a four-point Likert-scale and providing written feedback. The core group revised the draft priorities between rounds. In R2, panellists also ranked the priorities within six domains: epidemiology, models of care, treatment and care, education and awareness, patient and community perspectives, and leadership and public health policy. RESULTS: The consensus-built fatty liver disease research agenda encompasses 28 priorities. The mean percentage of 'agree' responses increased from 78.3 in R1 to 81.1 in R2. Five priorities received unanimous combined agreement ('agree' + 'somewhat agree'); the remaining 23 priorities had >90% combined agreement. While all but one of the priorities exhibited at least a super-majority of agreement (>66.7% 'agree'), 13 priorities had <80% 'agree', with greater reliance on 'somewhat agree' to achieve >90% combined agreement. CONCLUSIONS: Adopting this multidisciplinary consensus-built research priorities agenda can deliver a step-change in addressing fatty liver disease, mitigating against its individual and societal harms and proactively altering its natural history through prevention, identification, treatment, and care. This agenda should catalyse the global health community's efforts to advance and accelerate responses to this widespread and fast-growing public health threat. IMPACT AND IMPLICATIONS: An estimated 38% of adults and 13% of children and adolescents worldwide have fatty liver disease, making it the most prevalent liver disease in history. Despite substantial scientific progress in the past three decades, the burden continues to grow, with an urgent need to advance understanding of how to prevent, manage, and treat the disease. Through a global consensus process, a multidisciplinary group agreed on 28 research priorities covering a broad range of themes, from disease burden, treatment, and health system responses to awareness and policy. The findings have relevance for clinical and non-clinical researchers as well as funders working on fatty liver disease and non-communicable diseases more broadly, setting out a prioritised, ranked research agenda for turning the tide on this fast-growing public health threat.

Socioeconomic Factors Associated With Liver-Related Mortality From 1985 to 2015 in 36 Developed Countries.

BACKGROUND & AIMS: There is increasing disparity in liver-related mortality worldwide. Although there are many biologic and lifestyle risk factors for liver-related mortality, the effects of inequalities in social and economic determinants of health have received little attention. We investigated changes in liver-related mortality from 1985 through 2015 in 36 countries, using 4 international health and economic databases, and searched for socioeconomic factors that might influence these trends. METHODS: We collected information on sex- and country-specific liver-related mortality from countries with designated high-usability data from the World Health Organization mortality database. We obtained data on alcohol consumption per capita, the percentage of adults with a body mass index greater than 30 kg/m2, health expenditure per capita, gross domestic product per capita, Gini index, national unemployment estimates, and diabetes prevalence from the World Health Organization global health observatory data repository, the World Bank database, and the International Diabetes Federation. We examined changes in mortality using Joinpoint regression analysis. Univariate analysis and a mixed-effects linear model were used to identify factors associated with liver-related mortality. RESULTS: From 1985 to 2015, the mean liver-related deaths per 100,000 persons increased in men from 23.8 to 26.1, and in women from 9.7 to 11.9. Increased liver-related mortality was associated with male sex, a high level of alcohol consumption, obesity, and indicators of national wealth and government health expenditure gross domestic product or government expenditure on health. CONCLUSIONS: In addition to established risk factors for liver mortality, this study identified addressable economic factors associated with liver-related mortality trends. Health care professionals and policy makers may wish to consider these factors to reduce liver-related mortality.

Stat2 loss disrupts damage signalling and is protective in acute pancreatitis.

The severity of sterile inflammation, as seen in acute pancreatitis, is determined by damage-sensing receptors, signalling cascades and cytokine production. Stat2 is a type I interferon signalling mediator that also has interferon-independent roles in murine lipopolysaccharide-induced NF-κB-mediated sepsis. However, its role in sterile inflammation is unknown. We hypothesised that Stat2 determines the severity of non-infective inflammation in the pancreas. Wild type (WT) and Stat2-/- mice were injected i.p. with caerulein or l-arginine. Specific cytokine-blocking antibodies were used in some experiments. Pancreata and blood were harvested 1 and 24 h after the final dose of caerulein and up to 96 h post l-arginine. Whole-tissue phosphoproteomic changes were assessed using label-free mass spectrometry. Tissue-specific Stat2 effects were studied in WT/Stat2-/- bone marrow chimera and using Cre-lox recombination to delete Stat2 in pancreatic and duodenal homeobox 1 (Pdx1)-expressing cells. Stat2-/- mice were protected from caerulein- and l-arginine-induced pancreatitis. Protection was independent of type I interferon signalling. Stat2-/- mice had lower cytokine levels, including TNF-α and IL-10, and reduced NF-κB nuclear localisation in pancreatic tissue compared with WT. Inhibition of TNF-α improved (inhibition of IL-10 worsened) caerulein-induced pancreatitis in WT but not Stat2-/- mice. Phosphoproteomics showed downregulation of MAPK mediators but accumulation of Ser412-phosphorylated Tak1. Stat2 deletion in Pdx1-expressing acinar cells (Stat2flox/Pdx1-cre ) reduced pancreatic TNF-α expression, but not histological injury or serum amylase. WT/Stat2-/- bone marrow chimera mice were protected from pancreatitis irrespective of host or recipient genotype. Stat2 loss results in disrupted signalling in pancreatitis, upstream of NF-κB in non-acinar and/or bone marrow-derived cells. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Factors influencing longitudinal changes of circulating liver enzyme concentrations in subjects randomized to placebo in four clinical trials.

Liver enzyme concentrations are measured as safety end points in clinical trials to detect drug-related hepatotoxicity, but little is known about the epidemiology of these biomarkers in subjects without hepatic dysfunction who are enrolled in drug trials. We studied alanine and aspartate aminotransferase (ALT and AST) in subjects randomized to placebo who completed assessments over 36 mo in a cardiovascular outcome trial [the Stabilisation of Atherosclerotic Plaque by Initiation of Darapladib Therapy ("STABILITY") trial; n = 4,264; mean age: 64.2 yr] or over 12 mo in three trials that enrolled only subjects with type 2 diabetes (T2D) [the DIA trials; n = 308; mean age: 62.4 yr] to investigate time-dependent relationships and the factors that might affect ALT and AST, including body mass index (BMI), T2D, and renal function. Multivariate linear mixed models examined time-dependent relationships between liver enzyme concentrations as response variables and BMI, baseline T2D status, hemoglobin A1c levels, and renal function, as explanatory variables. At baseline, ALT was higher in individuals who were men, <65 yr old, and obese and who had glomerular filtration rate (GFR) >60 ml·min-1·1.73 m-2. ALT was not significantly associated with T2D at baseline, although it was positively associated with HbA1c. GFR had a greater impact on ALT than T2D. ALT concentrations decreased over time in subjects who lost weight but remained stable in individuals with increasing BMI. Weight change did not alter AST concentrations. We provide new insights on the influence of time, GFR, and HbA1c on ALT and AST concentrations and confirm the effect of sex, age, T2D, BMI, and BMI change in subjects receiving placebo in clinical trials. NEW & NOTEWORTHY Clinical trials provide high-quality data on liver enzyme concentrations from subjects randomized to placebo that can be used to investigate the epidemiology of these biomarkers. The adjusted models show the influence of sex, age, time, renal function, type 2 diabetes, HbA1c, and body mass index on alanine aminotransferase and aspartate aminotransferase concentrations and their relative importance. These factors need to be considered when assessing potential signals of hepatotoxicity in trials of new drugs and in clinical trials investigating subjects with nonalcoholic fatty liver disease.

Risks and clinical predictors of cirrhosis and hepatocellular carcinoma diagnoses in adults with diagnosed NAFLD: real-world study of 18 million patients in four European cohorts.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a common condition that progresses in some patients to steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). Here we used healthcare records of 18 million adults to estimate risk of acquiring advanced liver disease diagnoses in patients with NAFLD or NASH compared to individually matched controls. METHODS: Data were extracted from four European primary care databases representing the UK, Netherlands, Italy and Spain. Patients with a recorded diagnosis of NAFLD or NASH (NAFLD/NASH) were followed up for incident cirrhosis and HCC diagnoses. Each coded NAFLD/NASH patient was matched to up to 100 "non-NAFLD" patients by practice site, gender, age ± 5 years and visit recorded within ± 6 months. Hazard ratios (HR) were estimated using Cox models adjusted for age and smoking status and pooled across databases by random effects meta-analyses. RESULTS: Out of 18,782,281 adults, we identified 136,703 patients with coded NAFLD/NASH. Coded NAFLD/NASH patients were more likely to have diabetes, hypertension and obesity than matched controls. HR for cirrhosis in patients compared to controls was 4.73 (95% CI 2.43-9.19) and for HCC, 3.51 (95% CI 1.72-7.16). HR for either outcome was higher in patients with NASH and those with high-risk Fib-4 scores. The strongest independent predictor of a diagnosis of HCC or cirrhosis was baseline diagnosis of diabetes. CONCLUSIONS: Real-world population data show that recorded diagnosis of NAFLD/NASH increases risk of life-threatening liver outcomes. Diabetes is an independent predictor of advanced liver disease diagnosis, emphasising the need to identify specific groups of patients at highest risk.

Real-world data reveal a diagnostic gap in non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease worldwide. It affects an estimated 20% of the general population, based on cohort studies of varying size and heterogeneous selection. However, the prevalence and incidence of recorded NAFLD diagnoses in unselected real-world health-care records is unknown. We harmonised health records from four major European territories and assessed age- and sex-specific point prevalence and incidence of NAFLD over the past decade. METHODS: Data were extracted from The Health Improvement Network (UK), Health Search Database (Italy), Information System for Research in Primary Care (Spain) and Integrated Primary Care Information (Netherlands). Each database uses a different coding system. Prevalence and incidence estimates were pooled across databases by random-effects meta-analysis after a log-transformation. RESULTS: Data were available for 17,669,973 adults, of which 176,114 had a recorded diagnosis of NAFLD. Pooled prevalence trebled from 0.60% in 2007 (95% confidence interval: 0.41-0.79) to 1.85% (0.91-2.79) in 2014. Incidence doubled from 1.32 (0.83-1.82) to 2.35 (1.29-3.40) per 1000 person-years. The FIB-4 non-invasive estimate of liver fibrosis could be calculated in 40.6% of patients, of whom 29.6-35.7% had indeterminate or high-risk scores. CONCLUSIONS: In the largest primary-care record study of its kind to date, rates of recorded NAFLD are much lower than expected suggesting under-diagnosis and under-recording. Despite this, we have identified rising incidence and prevalence of the diagnosis. Improved recognition of NAFLD may identify people who will benefit from risk factor modification or emerging therapies to prevent progression to cardiometabolic and hepatic complications.

Inflammatory and Immune Responses to Surgery and Their Clinical Impact.

OBJECTIVE: The aim of this study was to describe current understanding of the local and systemic immune responses to surgery and their impact on clinical outcomes, predictive biomarkers, and potential treatment strategies. BACKGROUND: Patients undergoing major surgery are at risk of life-threatening inflammatory complications that include infection, the systemic inflammatory response syndrome (SIRS), or sepsis. Although improvements in surgical technique and peri-operative care have resulted in reduction in the rates of these complications, they remain high, especially in patients undergoing complex abdominal procedures. There are currently no drugs licensed specifically for the treatment of sepsis nor is it possible to identify those at highest risk, which would allow pre-emptive therapy that may improve outcomes. CONCLUSIONS: Local immune responses to surgery lead to systemic pro-inflammatory and immunosuppressive phases that are temporally related and proportionate in magnitude. Improved understanding of these mechanisms has implications for clinical study design and has led to the emergence of novel biomarkers such as Toll-like receptor expression. These can be used to stratify patient care pathways to maximize the benefit from current therapies or to select the right target at the right phase of illness for future drug development.

Systemic Inflammatory Response Syndrome After Major Abdominal Surgery Predicted by Early Upregulation of TLR4 and TLR5.

OBJECTIVES: To study innate immune pathways in patients undergoing hepatopancreaticobiliary surgery to understand mechanisms leading to enhanced inflammatory responses and identifying biomarkers of adverse clinical consequences. BACKGROUND: Patients undergoing major abdominal surgery are at risk of life-threatening systemic inflammatory response syndrome (SIRS) and sepsis. Early identification of at-risk patients would allow tailored postoperative care and improve survival. METHODS: Two separate cohorts of patients undergoing major hepatopancreaticobiliary surgery were studied (combined n = 69). Bloods were taken preoperatively, on day 1 and day 2 postoperatively. Peripheral blood mononuclear cells and serum were separated and immune phenotype and function assessed ex vivo. RESULTS: Early innate immune dysfunction was evident in 12 patients who subsequently developed SIRS (postoperative day 6) compared with 27 who did not, when no clinical evidence of SIRS was apparent (preoperatively or days 1 and 2). Serum interleukin (IL)-6 concentration and monocyte Toll-like receptor (TLR)/NF-κB/IL-6 functional pathways were significantly upregulated and overactive in patients who developed SIRS (P < 0.0001). Interferon α-mediated STAT1 phosphorylation was higher preoperatively in patients who developed SIRS. Increased TLR4 and TLR5 gene expression in whole blood was demonstrated in a separate validation cohort of 30 patients undergoing similar surgery. Expression of TLR4/5 on monocytes, particularly intermediate CD14CD16 monocytes, on day 1 or 2 predicted SIRS with accuracy 0.89 to 1.0 (areas under receiver operator curves). CONCLUSIONS: These data demonstrate the mechanism for IL-6 overproduction in patients who develop postoperative SIRS and identify markers that predict patients at risk of SIRS 5 days before the onset of clinical signs.

Stat2 loss leads to cytokine-independent, cell-mediated lethality in LPS-induced sepsis.

Deregulated Toll-like receptor (TLR)-triggered inflammatory responses that depend on NF-κB are detrimental to the host via excessive production of proinflammatory cytokines, including TNF-α. Stat2 is a critical component of type I IFN signaling, but it is not thought to participate in TLR signaling. Our study shows that LPS-induced lethality in Stat2(-/-) mice is accelerated as a result of increased cellular transmigration. Blocking intercellular adhesion molecule-1 prevents cellular egress and confers survival of Stat2(-/-) mice. The main determinant of cellular egress in Stat2(-/-) mice is the genotype of the host and not the circulating leukocyte. Surprisingly, lethality and cellular egress observed on Stat2(-/-) mice are not associated with excessive increases in classical sepsis cytokines or chemokines. Indeed, in the absence of Stat2, cytokine production in response to multiple TLR agonists is reduced. We find that Stat2 loss leads to reduced expression of NF-κB target genes by affecting nuclear translocation of NF-κB. Thus, our data reveal the existence of a different mechanism of LPS-induced lethality that is independent of NF-κB triggered cytokine storm but dependent on cellular egress.

Translating the potential of the urine steroid metabolome to stage NAFLD (TrUSt-NAFLD): study protocol for a multicentre, prospective validation study.

INTRODUCTION: Non-alcoholic fatty liver disease (NAFLD) affects approximately one in four individuals and its prevalence continues to rise. The advanced stages of NAFLD with significant liver fibrosis are associated with adverse morbidity and mortality outcomes. Currently, liver biopsy remains the 'gold-standard' approach to stage NAFLD severity. Although generally well tolerated, liver biopsies are associated with significant complications, are resource intensive, costly, and sample only a very small area of the liver as well as requiring day case admission to a secondary care setting. As a result, there is a significant unmet need to develop non-invasive biomarkers that can accurately stage NAFLD and limit the need for liver biopsy. The aim of this study is to validate the use of the urine steroid metabolome as a strategy to stage NAFLD severity and to compare its performance against other non-invasive NAFLD biomarkers. METHODS AND ANALYSIS: The TrUSt-NAFLD study is a multicentre prospective test validation study aiming to recruit 310 patients with biopsy-proven and staged NAFLD across eight centres within the UK. 150 appropriately matched control patients without liver disease will be recruited through the Oxford Biobank. Blood and urine samples, alongside clinical data, will be collected from all participants. Urine samples will be analysed by liquid chromatography-tandem mass spectroscopy to quantify a panel of predefined steroid metabolites. A machine learning-based classifier, for example, Generalized Matrix Relevance Learning Vector Quantization that was trained on retrospective samples, will be applied to the prospective steroid metabolite data to determine its ability to identify those patients with advanced, as opposed to mild-moderate, liver fibrosis as a consequence of NAFLD. ETHICS AND DISSEMINATION: Research ethical approval was granted by West Midlands, Black Country Research Ethics Committee (REC reference: 21/WM/0177). A substantial amendment (TrUSt-NAFLD-SA1) was approved on 26 November 2021. TRIAL REGISTRATION NUMBER: ISRCTN19370855.

Progress is impossible without change: understanding the evolving nomenclature of steatotic liver disease and its effect on hepatology practice.

The American, European, and Latin American liver societies have proposed a change in the nomenclature we use to describe alcohol-related liver disease and non-alcoholic fatty liver disease. Additionally, a term encompassing both is now advocated: steatotic liver disease, which includes metabolic dysfunction associated steatotic liver disease (MASLD) and MASLD with greater alcohol consumption (MetALD). These classifications offer increased relevance for clinicians, researchers, and patients alike. In this Viewpoint, we discuss the basis for this nomenclature shift and how it was developed. We also explore the challenges that will be faced in the adoption of such change. The proposed change seeks to banish stigma associated with phrasing such as alcoholic and fatty. However stigma, particularly related to the term fatty, is culturally nuanced, and reflects different entities depending on location. If such a change is internationally accepted, there will be wide-reaching effects on practitioners in primary care and metabolic medicine, and on patients. We discuss those effects and the opportunities the nomenclature change could offer, particularly for patients with alcohol and metabolic risk factors who represent a group previously ignored by clinical trials.

National study of NAFLD management identifies variation in delivery of care in the UK between 2019 to 2022.

Background & Aims: Non-alcoholic fatty liver disease (NAFLD) is associated with liver and cardiovascular morbidity and mortality. Recently published NAFLD Quality Standards include 11 key performance indicators (KPIs) of good clinical care. This national study, endorsed by British Association for the Study of the Liver (BASL) and British Society of Gastroenterology (BSG), aimed to benchmark NAFLD care in UK hospitals against these KPIs. Methods: This study included all new patients with NAFLD reviewed in the outpatient clinic in the months of March 2019 and March 2022. Participating UK hospitals self-registered for the study through BASL/BSG. KPI outcomes were compared using Fisher's exact or Chi-square tests. Results: Data from 776 patients with NAFLD attending 34 hospitals (England [25], Scotland [four], Wales [three], Northern Ireland [two]) were collected. A total of 85.3% of hospitals reported established local liver disease assessment pathways, yet only 27.9% of patients with suspected NAFLD had non-invasive fibrosis assessment documented at the point of referral to secondary care. In secondary care, 79.1% of patients had fibrosis assessment. Assessment of cardiometabolic risk factors including obesity, type 2 diabetes, hypertension, and smoking were conducted in 73.2%, 33.0%, 19.3%, and 54.9% of all patients, respectively. There was limited documentation of diet (35.7%) and exercise advice (55.1%). Excluding those on statins, only 9.1% of patients with NAFLD at increased cardiovascular risk (T2DM and/or QRISK-3 >10%) had documented discussion of statin treatment. Significant KPI improvements from 2019 to 2022 were evident in use of non-invasive fibrosis assessment before secondary care referral, statin recommendations, and diet and exercise recommendations. Conclusions: This national study identified substantial variation in NAFLD management in the UK with clear areas for improvement, particularly fibrosis risk assessment before secondary care referral and management of associated cardiometabolic risk factors. Impact and implications: This study identified significant variation in the management of NAFLD in the UK. Only 27.9% of patients with suspected NAFLD had non-invasive fibrosis assessment performed to identify those at greater risk of advanced liver disease before specialist referral. Greater emphasis is needed on the management of associated cardiometabolic risk factors in individuals with NAFLD. Hospitals with multidisciplinary NAFLD service provision had higher rates of fibrosis evaluation and assessment and management of cardiometabolic risk than hospitals without multidisciplinary services. Further work is needed to align guideline recommendations and real-world practice in NAFLD care.

Feasibility and acceptability of a primary care liver fibrosis testing pathway centred on the diabetes annual review: PRELUDE1 prospective cohort study protocol.

INTRODUCTION: Non-alcoholic fatty liver disease is the most common chronic liver disease worldwide affecting 20%-25% in the USA and Europe with a 60%-80% lifetime prevalence for people with type 2 diabetes (T2D). Fibrosis has repeatedly been demonstrated to be the major determinant of liver disease morbidity and mortality and there is currently no routine screening for liver fibrosis in at-risk T2D population. METHODS AND ANALYSIS: This 12-month prospective cohort study of automated fibrosis testing uses the fibrosis-4 score (FIB-4) in patients with T2D linked to the investigation of hospital-based versus community-based second-tier transient elastography (TE) testing. We plan to include >5000 participants across 10 General Practitioner (GP) practices in East London and Bristol. This will determine the rate of undiagnosed significant liver fibrosis in a T2D population, the feasibility of two-tier liver fibrosis screening using FIB-4 at the diabetes annual review and subsequent TE delivered either in the community or secondary care settings. This will include an intention-to-treat analysis for all those invited to attend for diabetes annual review. A qualitative substudy regarding the acceptability of the fibrosis screening pathway will comprise semistructured interviews/focus groups with primary care staff (GPs and practice nurses), and patients taking part in the wider study. ETHICS AND DISSEMINATION: This study received a favourable opinion from the Cambridge East research ethics committee. The results of this study will be disseminated in peer-reviewed scientific journals, conference presentations and local diabetes lay panel meetings. TRIAL REGISTRATION NUMBER: ISRCTN14585543.

Single-cell phenotypes of peripheral blood immune cells in early and late stages of non-alcoholic fatty liver disease.

BACKGROUND/AIMS: Immune and inflammatory cells respond to multiple pathological hits in the development of nonalcoholic steatohepatitis (NASH) and fibrosis. Relatively little is known about how their type and function change through the non-alcoholic fatty liver disease (NAFLD) spectrum. Here we used multi-dimensional mass cytometry and a tailored bioinformatic approach to study circulating immune cells sampled from healthy individuals and people with NAFLD. METHODS: Cytometry by time of flight using 36 metal-conjugated antibodies was applied to peripheral blood mononuclear cells (PBMCs) from biopsy-proven NASH fibrosis (late disease), steatosis (early disease), and healthy patients. Supervised and unsupervised analyses were used, findings confirmed, and mechanisms assessed using independent healthy and disease PBMC samples. RESULTS: Of 36 PBMC clusters, 21 changed between controls and disease samples. Significant differences were observed between diseases stages with changes in T cells and myeloid cells throughout disease and B cell changes in late stages. Semi-supervised gating and re-clustering showed that disease stages were associated with fewer monocytes with active signalling and more inactive NK cells; B and T cells bearing activation markers were reduced in late stages, while B cells bearing co-stimulatory molecules were increased. Functionally, disease states were associated with fewer activated mucosal-associated invariant T cells and reduced toll-like receptor-mediated cytokine production in late disease. CONCLUSION: A range of innate and adaptive immune changes begin early in NAFLD, and disease stages are associated with a functionally less active phenotype compared to controls. Further study of the immune response in NAFLD spectrum may give insight into mechanisms of disease with potential clinical application.