Macrophage activation markers are associated with infection and mortality in patients with acute liver failure.

BACKGROUND AND AIMS: Acute liver failure is a multisystem disorder with a high mortality and frequent need for emergency liver transplantation. Following massive innate immune system activation, soluble markers of macrophage activation are released during liver damage and their association with disease severity and prognosis requires exploration. METHODS: Patients ALF from the United States Acute Liver Failure Study Group (USALFSG, n = 224) and King's College Hospital (n = 40) together with healthy controls (HC, n = 50) were recruited. Serum from early (Days 1-3) and late (>Day 3) time points were analysed for MAMs by enzyme-linked immunosorbent assay correlated to markers of illness severity and 21-day spontaneous survival. Surface expression phenotyping was performed via Flow Cytometry on CD14+ monocytes. RESULTS: All MAMs serum concentrations were significantly higher in ALF compared to controls (p < .0001). sCD206 concentration was higher in early and late stages of the disease in patients with bacteraemia (p = .002) and infection in general (p = .006). In MELD-adjusted multivariate modelling, sCD206 and sCD163 were independently associated with mortality. CD14+ monocyte expression of CD206 (p < .001) was higher in patients with ALF compared with controls and correlated with SOFA score (p = .018). sCD206 was independently validated as a predictor of infection in an external cohort. CONCLUSIONS: sCD206 is increased in serum of ALF patients with infections and poor outcome and is upregulated on CD14+ monocytes. Later measurements of sCD163 and sCD206 during the evolution of ALF have potential as mechanistic predictors of mortality. sCD206 should be explored as a biomarker of sepsis and mortality in ALF.

Lysophosphatidylcholines modulate immunoregulatory checkpoints in peripheral monocytes and are associated with mortality in people with acute liver failure.

BACKGROUND & AIMS: Acute liver failure (ALF) is a life-threatening disease characterised by high-grade inflammation and immunoparesis, which is associated with a high incidence of death from sepsis. Herein, we aimed to describe the metabolic dysregulation in ALF and determine whether systemic immune responses are modulated via the lysophosphatidylcholine (LPC)-autotaxin (ATX)-lysophosphatidylcholinic acid (LPA) pathway. METHODS: Ninety-six individuals with ALF, 104 with cirrhosis, 31 with sepsis and 71 healthy controls (HCs) were recruited. Pathways of interest were identified by multivariate statistical analysis of proton nuclear magnetic resonance spectroscopy and untargeted ultraperformance liquid chromatography-mass spectrometry-based lipidomics. A targeted metabolomics panel was used for validation. Peripheral blood mononuclear cells were cultured with LPA 16:0, 18:0, 18:1, and their immune checkpoint surface expression was assessed by flow cytometry. Transcript-level expression of the LPA receptor (LPAR) in monocytes was investigated and the effect of LPAR antagonism was also examined in vitro. RESULTS: LPC 16:0 was highly discriminant between ALF and HC. There was an increase in ATX and LPA in individuals with ALF compared to HCs and those with sepsis. LPCs 16:0, 18:0 and 18:1 were reduced in individuals with ALF and were associated with a poor prognosis. Treatment of monocytes with LPA 16:0 increased their PD-L1 expression and reduced CD155, CD163, MerTK levels, without affecting immune checkpoints on T and NK/CD56+T cells. LPAR1 and 3 antagonism in culture reversed the effect of LPA on monocyte expression of MerTK and CD163. MerTK and CD163, but not LPAR genes, were differentially expressed and upregulated in monocytes from individuals with ALF compared to controls. CONCLUSION: Reduced LPC levels are biomarkers of poor prognosis in individuals with ALF. The LPC-ATX-LPA axis appears to modulate innate immune response in ALF via LPAR1 and LPAR3. Further investigations are required to identify novel therapeutic agents targeting these receptors. IMPACT AND IMPLICATIONS: We identified a metabolic signature of acute liver failure (ALF) and investigated the immunometabolic role of the lysophosphatidylcholine-autotaxin-lysophosphatidylcholinic acid pathway, with the aim of finding a mechanistic explanation for monocyte behaviour and identifying possible therapeutic targets (to modulate the systemic immune response in ALF). At present, no selective immune-based therapies exist. We were able to modulate the phenotype of monocytes in vitro and aim to extend these findings to murine models of ALF as a next step. Future therapies may be based on metabolic modulation; thus, the role of specific lipids in this pathway require elucidation and the relative merits of autotaxin inhibition, lysophosphatidylcholinic acid receptor blockade or lipid-based therapies need to be determined. Our findings begin to bridge this knowledge gap and the methods used herein could be useful in identifying therapeutic targets as part of an experimental medicine approach.

Immunometabolic analysis shows a distinct cyto-metabotype in Covid-19 compared to sepsis from other causes.

Background: In Covid-19, profound systemic inflammatory responses are accompanied by both metabolic risk factors for severity and, separately, metabolic mechanisms have been shown to underly disease progression. It is unknown whether this reflects similar situations in sepsis or is a unique characteristic of Covid-19. Aims: Define the immunometabolic signature of Covid-19. Methods: 65 patients with Covid-19,19 patients with sepsis and 14 healthy controls were recruited and sampled for plasma, serum and peripheral blood mononuclear cells (PBMCs) through 10 days of critical illness. Metabotyping was performed using the Biocrates p180 kit and multiplex cytokine profiling undertaken. PBMCs underwent phenotyping by flow cytometry. Immune and metabolic readouts were integrated and underwent pathway analysis. Results: Phopsphatidylcholines (PC) are reduced in Covid-19 but greater than in sepsis. Compared to controls, tryptophan is reduced in Covid-19 and inversely correlated with the severity of the disease and IFN-É£ concentrations, conversely the kyneurine and kyneurine/tryptophan ratio increased in the most severe cases. These metabolic changes were consistent through 2 pandemic waves in our centre. PD-L1 expression in CD8+ T cells, Tregs and CD14+ monocytes was increased in Covid-19 compared to controls. Conclusions: In our cohort, Covid-19 is associated with monocytopenia, increased CD14+ and Treg PD-L1 expression correlating with IFN-É£ plasma concentration and disease severity (SOFA score). The latter is also associated with metabolic derangements of Tryptophan, LPC 16:0 and PCs. Lipid metabolism, in particular phosphatidylcholines and lysophosphatidylcolines, seems strictly linked to immune response in Covid-19. Our results support the hypothesis that IFN-É£ -PD-L1 axis might be involved in the cytokine release syndrome typical of severe Covid-19 and the phenomenon persisted through multiple pandemic waves despite use of immunomodulation.

Systematic review and meta-analysis of the diagnostic accuracy of procalcitonin for post-operative sepsis/infection in liver transplantation.

BACKGROUND: Post-operative infection is a major cause of morbidity and mortality in Liver Transplantation (LT). Early diagnosis and antimicrobial treatment improves outcomes and ruling out sepsis aids immunosuppression decisions. Procalcitonin (PCT) has recently become part of such decision making in COVID-19 pneumonia but its role in LT is not established. We assessed the diagnostic accuracy of PCT as a diagnostic biomarker for infection or sepsis following LT. METHODS: A systematic search was conducted for studies reporting diagnostic performance of PCT for infection/sepsis following LT. Studies were assessed for reporting of diagnostic accuracy, relevance and quality. RESULTS: Eight studies with 363 participants reported data on the diagnostic accuracy of PCT, with pooled sensitivity, specificity, diagnostic odds ratio and summary receiver operator curve of 70% (95% CI 62-78), 77% (95% CI 73-83), 15.82 (95% CI 5.82-43.12) and 0.871 respectively. There was variability in the timing of sampling (post-operative day 1-8) and range of cut-off values (0.48 to 42.8 ng/mL). Heterogeneity was reduced when only studies with adult LT recipients were considered. CONCLUSIONS: PCT performs moderately well as a diagnostic test for postoperative infection/sepsis following LT. This marker is more suited for use in adult LT populations.

Acute liver failure.

PURPOSE OF REVIEW: Present an outline of acute liver failure, from its definition to its management in critical care, updated with findings of selected newer research. RECENT FINDINGS: Survival of patients with acute liver failure has progressively improved. Intracranial hypertension complicating hepatic encephalopathy is now much less frequent than in the past and invasive ICP monitoring is now rarely used. Early renal replacement therapy and possibly therapeutic plasma exchange have consolidated their role in the treatment. Further evidence confirms the low incidence of bleeding in these patients despite striking abnormalities in standard tests of coagulation and new findings of abnormalities on thromboelastographic testing. Specific coagulopathy profiles including an abnormal vWF/ADAMTS13 ratio may be associated with poor outcome and increased bleeding risk. Use of N-acetylcysteine in nonparacetamol-related cases remains unsupported by robust clinical evidence. New microRNA-based prognostic markers to select patients for transplantation are described but are still far from widespread clinical applicability; imaging-based prognostication tools are also promising. The use of extracorporeal artificial liver devices in clinical practice is yet to be supported by evidence. SUMMARY: Medical treatment of patients with acute liver failure is now associated with significantly improved survival. Better prognostication and selection for emergency liver transplant may further improve care for these patients.

A case series of non-valvular cardiac aspergillosis in critically ill solid organ transplant and non-transplant patients and systematic review.

INTRODUCTION: Non-valvular cardiac aspergillosis is a rare infection of the pericardium, myocardium or endocardium and is associated with a high mortality. There is a paucity of reports of non-valvular cardiac aspergillosis in critically ill and solid organ transplant (SOT) patients. The majority of cases have been reported in haemato-oncology patients, some of whom have undergone a bone marrow transplant. OBJECTIVES: We describe four cases affected by non-valvular cardiac aspergillosis in the intensive care setting including a systematic review of this extremely rare infection which is associated with high mortality. RESULTS: All four-patients died but presented with varying clinical, radiological and microbiological evidence of the disease. Three patients presented following complications after solid organ transplantation, two in the context of acute liver failure and emergency liver transplant and one several years after a double lung transplant. The last patient presented with necrotising gall stone pancreatitis, multi-organ failure and subsequently a prolonged intensive care unit (ICU) stay. On review of the literature, January 1955 to July 2019, 45 cases were identified, with different risk factors, clinical and radiological manifestations, treatment regimen and outcome. CONCLUSION: Antemortem diagnosis of cardiac aspergillosis is difficult and rare, with no cases reporting positive blood culture results. Galactomannan serology has poor sensitivity in solid organ transplant patients, further reduced by prophylactic antimicrobial treatment, which is common in the ICU setting especially post-transplant patients. Due to the scarcity of cases, treatment is extrapolated from invasive aspergillosis management, with emphasis on early treatment with combination therapy.

Leucocyte ratios are biomarkers of mortality in patients with acute decompensation of cirrhosis and acute-on-chronic liver failure.

BACKGROUND: In patients with cirrhosis, progression to acute decompensation (AD) and acute-on-chronic liver failure (ACLF) has been associated with poor prognosis. Differential leucocyte ratios might predict mortality in systemic inflammatory conditions. AIM: To evaluate differential leucocyte ratios as prognostic biomarkers in patients with cirrhosis. METHODS: Patients with AD and ACLF were recruited from four centres in three countries. Peripheral blood differential leucocytes were measured (three centres using flow cytometry) on hospital admission and at 48 hours. Ratios were correlated to model for end-stage liver disease (MELD), chronic liver failure-sequential organ failure (CLIF-SOFA), suspected/culture-positive bacterial infection and survival. RESULTS: Nine hundred twenty-six patients (562 (61%) male, median age 55 (25-94) years) were studied. Overall, 350 (37%) did not survive to hospital discharge. Neutrophil-lymphocyte ratio (NLR) and monocyte-lymphocyte ratio (MLR) were elevated in patients with AD and ACLF who died during their hospital stay. On multivariate analysis NLR retained statistical significance independently of CLIF-SOFA or MELD. NLR >30 was associated with an 80% 90-day mortality in patients with ACLF but not AD. On sensitivity analysis for subgroups (alcohol-related liver disease and suspected sepsis), NLR and MLR retained statistically robust accuracy for the prediction of mortality. Significant predictive accuracy was only observed in centres using flow cytometry. CONCLUSION: Leucocyte ratios are simple and robust biomarkers of outcome in ACLF, which are comparable to CLIF-SOFA score but dependent on leucocyte quantification method. NLR and MLR may be used as screening tools for mortality prediction in patients with acutely deteriorating cirrhosis.

Incidence, risk factors, and survival of hepatocellular carcinoma in primary biliary cirrhosis: comparative analysis from two centers.

UNLABELLED: The limited information and divergent results on the prevalence, incidence, and risk factors for hepatocellular carcinoma (HCC) in patients with primary biliary cirrhosis (PBC) may be due to the low prevalence of the disease and geographical and environmental differences. Therefore, we analyzed the incidence, prevalence, survival, and risk factors for HCC in patients with PBC from two European centers (389 from Barcelona, Spain, and 327 from Padova, Italy) followed up for 9.3 +/- 6.5 years. Gender, age, smoking habit, alcohol consumption, presence of hepatitis B surface antigen (HBsAg) or hepatitis C virus antibodies (anti-HCV), and advanced histological stage (III-IV) were evaluated as risk factors for tumor development. Twenty-four patients (13 from Barcelona and 11 from Padova) developed HCC. The prevalence of HCC was similar in Barcelona (3.34%) and Padova (3.36%). The incidence was 0.35 and 0.37 per 100 patient-years, respectively. Male gender, age >52 years, smoking habit, alcohol >40 g/day, HBsAg, and anti-HCV were not associated with HCC. Advanced histological stage was the only factor associated with the development of HCC (odds ratio [OR]: 5.80, 95% confidence interval [CI]: 2.34-14.38, P < 0.001). When analyzing the two series separately, male gender was associated with higher likelihood of HCC in Padova (OR: 8.09, 95% CI: 1.93-33.8, P < 0.01). The median survival after the diagnosis of HCC was 36 months. CONCLUSION: The prevalence and incidence of HCC is similar in Spain and Italy and the advanced histological stage is the only risk factor associated with the development of HCC in PBC. The slight disparities observed between the two series might be explained by patient features on diagnosis of liver disease.