Beneficial role of G-CSF in acute-on-chronic liver failure: effects on liver regeneration, inflammation/immunoparalysis or both?

Challenges in Diagnosis and Therapeutic Approach of Acute on Chronic Liver Failure-A Review of Current Evidence

Acute-on-chronic liver failure (ACLF) is a syndrome characterized by acute and severe decompensation of chronic liver disease (CLD) correlated with multiple organ failure, poor prognosis, and increased mortality. In 40-50% of ACLF cases, the trigger is not recognized; for many of these patients, bacterial translocation associated with systemic inflammation is thought to be the determining factor; in the other 50% of patients, sepsis, alcohol consumption, and reactivation of chronic viral hepatitis are the most frequently described trigger factors. Other conditions considered precipitating factors are less common, including acute alcoholic hepatitis, major surgery, TIPS insertion, or inadequate paracentesis without albumin substitution. Host response is likely the primary factor predicting ACLF severity and prognosis, the host immune response having a particular significance in this syndrome, together with the inflammatory cascade. The management of ACLF includes both the prevention of the precipitating factors that lead to acute liver decompensation and the support of vital functions, the prevention and management of complications, the estimation of prognosis, and the opportunity for liver transplantation.

The Mechanisms of Systemic Inflammatory and Immunosuppressive Acute-on-Chronic Liver Failure and Application Prospect of Single-Cell Sequencing

Acute-on-chronic liver failure (ACLF) is a complex clinical syndrome, and patients often have high short-term mortality. It occurs with intense systemic inflammation, often accompanied by a proinflammatory event (such as infection or alcoholic hepatitis), and is closely related to single or multiple organ failure. Liver inflammation begins when innate immune cells (such as Kupffer cells (KCs)) are activated by binding of pathogen-associated molecular patterns (PAMPs) from pathogenic microorganisms or damage-associated molecular patterns (DAMPs) of host origin to their pattern recognition receptors (PRRs). Activated KCs can secrete inflammatory factors as well as chemokines and recruit bone marrow-derived cells such as neutrophils and monocytes to the liver to enhance the inflammatory process. Bacterial translocation may contribute to ACLF when there are no obvious precipitating events. Immunometabolism plays an important role in the process (including mitochondrial dysfunction, amino acid metabolism, and lipid metabolism). The late stage of ACLF is mainly characterized by immunosuppression. In this process, the dysfunction of monocyte and macrophage is reflected in the downregulation of HLA-DR and upregulation of MER tyrosine kinase (MERTK), which weakens the antigen presentation function and reduces the secretion of inflammatory cytokines. We also describe the specific function of bacterial translocation and the gut-liver axis in the process of ACLF. Finally, we also describe the transcriptomics in HBV-ACLF and the recent progress of single-cell RNA sequencing as well as its potential application in the study of ACLF in the future, in order to gain a deeper understanding of ACLF in terms of single-cell gene expression.

G-CSF promotes the viability and angiogenesis of injured liver via direct effects on the liver cells

BACKGROUND

Presently, liver transplantation is the only treatment strategy for liver failure (LF). Although granulocyte-colony stimulating factor (G-CSF) exhibits protective functions in LF, it is not clear whether it directly affects the liver cells.

METHODS AND RESULTS

We established an injured liver cell model and observed that G-CSF treatment promoted cell viability and enhanced Ki67 and VEGF-A expression. Thereafter, human umbilical vein endothelial cells (HUVECs) were cultured in a conditioned medium collected from the G-CSF-treated injured liver cells. HUVECs' proliferation and tubule formation were promoted. Furthermore, in an injured liver mouse model, confirmed via haematoxylin-eosin staining, we evaluated serum alanine aminotransferase activity, Ki67 expression, and microvessel density (MVD). G-CSF treatment significantly relieved liver injury, upregulated Ki67 expression, and enhanced MVD in the injured mouse liver tissue. Additionally, AKT and ERK signal targets were explored, and it was demonstrated that the effects of G-CSF on injured liver cells were mediated through the AKT and ERK signalling pathways.

CONCLUSIONS

G-CSF promotes injured liver viability and angiogenesis by directly affecting injured liver cells via the AKT and ERK signalling pathways. These findings improve our understanding of the role of G-CSF in recovery from LF.

Alcohol and Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is a clinical syndrome that occurs in patients with cirrhosis and is characterised by acute deterioration, organ failure and high short-term mortality. Alcohol is one of the leading causes of ACLF and the most frequently reported aetiology of underlying chronic liver disease. Among patients with alcoholic hepatitis (AH), ACLF is a frequent and severe complication. It is characterised by both immune dysfunction associated to an increased risk of infection and high-grade systemic inflammation that ultimately induce organ failure. Diagnosis and severity of ACLF determine AH prognosis, and therefore, ACLF prognostic scores should be used in severe AH with organ failure. Corticosteroids remain the first-line treatment for severe AH but they seem insufficient when ACLF is associated. Novel therapeutic targets to contain the excessive inflammatory response and reduce infection have been identified and are under investigation. With liver transplantation remaining one of the most effective therapies for severe AH and ACLF, adequate organ allocation represents a growing challenge. Hence, a clear understanding of the pathophysiology, clinical implications and management strategies of ACLF in AH is essential for hepatologists, which is narrated briefly in this review.

Therapeutic Effect and Safety of Granulocyte Colony-Stimulating Factor Therapy for Acute-On-Chronic Liver Failure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background and Aims: Granulocyte colony-stimulating factor (G-CSF) has been proposed as a therapeutic option for patients with acute-on-chronic liver failure (ACLF). However, its clinical efficacy remains debatable. This study aimed to synthesize available evidence on the efficacy of G-CSF in ALCF.

Methods: The Cochrane Library, CNKI, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov were searched from inception until September 2021. After qualitative evaluation of the included literature, the included studies were analyzed.

Results: Seven studies were included in this meta-analysis. Overall, G-CSF therapy was not associated with a reduced risk of death (30-day survival, OR = 1.55, 95% CI: 1.00, 2.38, P = 0.05; 60-day survival, OR = 1.50, 95% CI: 0.95, 2.36, P = 0.08; 90-day survival, OR = 1.61, 95% CI: 0.99, 2.62, P = 0.05) or complication including occurrence of infections infection (OR = 0.66, 95% CI: 0.41, 1.05, P = 0.08), bleeding (OR = 1.50, 95% CI: 0.58, 3.89, P = 0.41), and hepatorenal syndrome (OR = 0.56, 95% CI: 0.25, 1.24, P = 0.15). Moreover, it had no obvious beneficial effects on the model of end-stage liver disease score (30-day SMD = −3.31, 95%CI: −7.42, 0.81, P = 0.12; 60-day SMD = −1.23, 95% CI: −5.21, 2.75, P = 0.54; 90-day SMD = −2.29, 95%CI: −4.94, 0.37, P = 0.09). Sensitivity analyses showed that patients in Asia had improved survival (30-day OR = 2.76, 95%CI: 1.43, 5.35, P = 0.003; 60-day OR = 2.83, 95% CI: 1.39, 5.73, P = 0.004; 90-day OR = 2.92, 95% CI: 1.34, 6.36, P = 0.007).

Conclusions: Our findings suggest that, currently, G-CSF cannot be recommended for the treatment of ACLF.

Effectiveness of granulocyte colony-stimulating factor for patients with acute-on-chronic liver failure: a meta-analysis

BACKGROUND

The safety and efficacy of granulocyte colony-stimulating factor (G-CSF) for the treatment of acute-on-chronic liver failure (ACLF) remain uncertain. Therefore, we conducted a meta-analysis to draw a firmer conclusion.

METHODS

We searched the Cochrane library, PubMed, Embase, and China Biology Medicine disc to identify relevant RCTs performed before January 2020. Risk ratios (RRs) and their 95% confidence intervals (95% CIs) were calculated using a random effects model.

MAIN OUTCOME MEASURES

RRs (95% CI) for 1-, 2-, and 3-month survival rates.

SAMPLE SIZE

Six RCTs, including three open-label studies.

RESULTS

The six studies included 246 subjects (121 in a G-CSF group and 125 in a control group). G-CSF administration significantly improved the 1-, 2-, and 3-month survival rates in patients with ACLF. The pooled RRs (95% CI, P) were 0.43 (0.27-0.69, P=.0004), 0.44 (0.32-0.62, P<.00001), and 0.39 (0.22-0.68, P=.0009), respectively.

CONCLUSION

G-CSF may be beneficial and effective in the treatment of ACLF, but further studies are needed to verify this conclusion.

LIMITATIONS

The sample size was small, and studies were restricted to countries in Asia.

PROSPERO REGISTRATION NUMBER

CRD42021225681 CONFLICT OF INTEREST: None.

Longitudinal effects of modified creatinine index on all-cause mortality in individuals receiving hemodialysis treatment

BACKGROUND

The modified creatinine index (mCI), as a surrogate marker of muscle mass, has been associated with poor outcomes in patients undergoing hemodialysis. However, a single assessment may not reflect the clinical significance before an adverse clinical endpoint.

OBJECTIVE

Analyze mCI trajectories and their association with all-cause mortality in incident hemodialysis patients.

DESIGN

Retrospective observational cohort.

SETTING

Outpatient dialysis facility.

PATIENTS AND METHODS

We followed a cohort of patients who underwent maintenance hemodialysis treatment at least three times weekly for at least three months from 19 June 2010 to 29 December 2017. Clinical and laboratory features were measured at baseline. Longitudinal changes in the mCI were modeled using a joint longitudinal and survival model adjusted for baseline covariates and body mass index trajectories.

MAIN OUTCOME MEASURE

All-cause mortality.

SAMPLE SIZE

408 with 208 males (50.7%).

RESULTS

The mean (SD) age was 62.2 (12.3) years. The mCI changes were evaluated for a median (interquartile range) follow-up of 2.16 (1.13, 3.73) years. Forty-six percent (n=188) of patients reached the endpoint. A steeper slope (per 0.1 unit increase in the decrease rate) in modified creatinine index was associated with increased risk of all-cause mortality (HR, 1.04; 95% CI, 1.02-1.07; P=.011). In addition, an annual 1 mg/kg/day decrease in modified creatinine index level increased the hazard of all-cause mortality by 4% (HR, 1.04; 95% CI, 1.02-1.07; P=.001).

LIMITATIONS

Residual kidney function was not observed in the data. Setting was single center and thus results may not be generalizable to other populations.

CONCLUSION

All-cause death was significantly associated with loss of muscle mass over time. Longitudinal trajectories of nutritional markers may predict the clinical outcomes in patients undergoing hemodialysis. This may also be valuable for individual risk stratification. Furthermore, early management may provide an opportunity to improve patient survival.

CONFLICT OF INTEREST

None.

Prevention of Cirrhosis Complications: Looking for Potential Disease Modifying Agents

The current therapeutic strategies for the management of patients with cirrhosis rely on the prevention or treatment of specific complications. The removal of the causative agents (i.e., viruses or alcohol) prevents decompensation in the vast majority of patients with compensated cirrhosis. In contrast, even when etiological treatment has been effective, a significant proportion of patients with decompensated cirrhosis remains at risk of further disease progression. Therefore, therapies targeting specific key points in the complex pathophysiological cascade of decompensated cirrhosis could represent a new approach for the management of these severely ill patients. Some of the interventions currently employed for treating or preventing specific complications of cirrhosis or used in other diseases (i.e., poorly absorbable oral antibiotics, statins, albumin) have been proposed as potential disease-modifying agents in cirrhosis (DMAC) since clinical studies have shown their capacity of improving survival. Additional multicenter, large randomized clinical trials are awaited to confirm these promising results. Finally, new drugs able to antagonize key pathophysiological mechanisms are under pre-clinical development or at the initial stages of clinical assessment.

Toll-like receptor 5-mediated signaling enhances liver regeneration in mice

BACKGROUND

Toll-like receptor 5 (TLR5)-mediated pathways play critical roles in regulating the hepatic immune response and show hepatoprotective effects in mouse models of hepatic diseases. However, the role of TLR5 in experimental models of liver regeneration has not been reported. This study aimed to investigate the role of TLR5 in partial hepatectomy (PHx)-induced liver regeneration.

METHODS

We performed 2/3 PHx in wild-type (WT) mice, TLR5 knockout mice, or TLR5 agonist CBLB502 treated mice, as a model of liver regeneration. Bacterial flagellin content was measured with ELISA, and hepatic TLR5 expression was determined with quantitative PCR analyses and flow cytometry. To study the effects of TLR5 on hepatocyte proliferation, we analyzed bromodeoxyuridine (BrdU) incorporation and proliferating cell nuclear antigen (PCNA) expression with immunohistochemistry (IHC) staining. The effects of TLR5 during the priming phase of liver regeneration were examined with quantitative PCR analyses of immediate early gene mRNA levels, and with Western blotting analysis of hepatic NF-κB and STAT3 activation. Cytokine and growth factor production after PHx were detected with real-time PCR and cytometric bead array (CBA) assays. Oil Red O staining and hepatic lipid concentrations were analyzed to examine the effect of TLR5 on hepatic lipid accumulation after PHx.

RESULTS

The bacterial flagellin content in the serum and liver increased, and the hepatic TLR5 expression was significantly up-regulated in WT mice after PHx. TLR5-deficient mice exhibited diminished numbers of BrdU- and PCNA-positive cells, suppressed immediate early gene expression, and decreased cytokine and growth factor production. Moreover, PHx-induced hepatic NF-κB and STAT3 activation was inhibited in Tlr5^-/- mice, as compared with WT mice. Consistently, the administration of CBLB502 significantly promoted PHx-mediated hepatocyte proliferation, which was correlated with enhanced production of proinflammatory cytokines and the recruitment of macrophages and neutrophils in the liver. Furthermore, Tlr5^-/- mice displayed significantly lower hepatic lipid concentrations and smaller Oil Red O positive areas than those in control mice after PHx.

CONCLUSION

We reveal that TLR5 activation contributes to the initial events of liver regeneration after PHx. Our findings demonstrate that TLR5 signaling positively regulates liver regeneration and suggest the potential of TLR5 agonist to promote liver regeneration.

Granulocyte colony-stimulating factor for alcoholic hepatitis: A systematic review and meta-analysis of randomised controlled trials

Background & Aims

Granulocyte colony-stimulating factor (G-CSF) treatment has been proposed as a therapeutic option for patients with severe alcoholic hepatitis (AH). The aim of this study was to synthesise available evidence on the efficacy of G-CSF in AH.

Methods

This is a meta-analysis of randomised controlled trials evaluating the risk of death at 90 days and the risk of infection.

Results

Seven studies were included. Of a total of 396 patients, 336 had AH, 197 patients were treated with G-CSF, and 199 received placebo or pentoxifylline. In overall meta-analysis, G-CSF therapy was associated with a reduced risk of death at 90 days (odds ratio [OR] 0.28; 95% CI 0.09–0.88; p = 0.03). There was high heterogeneity between studies (p <0.001; I² = 80%). Five studies were performed in Asia and 2 in Europe. In the subgroup analysis of studies performed in Asia, G-CSF was associated with a reduced risk of death (OR 0.15; 95% CI 0.08–0.28; p <0.001; heterogeneity: p = 0.5, I² = 0%). In European studies, G-CSF tended to increase mortality compared with controls, although the difference was not significant (OR 1.89; 95% CI 0.90–3.98; p = 0.09; heterogeneity: p = 0.8, I² = 0%). In Asian studies, occurrence of infection was less frequent in G-CSF patients than in controls (OR 0.12; 95% CI 0.06–0.23; p <0.001; heterogeneity: p = 0.7, I² = 0%), whilst in European studies, this occurrence was not statistically different (OR 0.92; 95% CI 0.50–1.68; p = 0.78; heterogeneity: p = 0.5, I² = 0%). In sensitivity analyses, excluding studies that included patients with acute-on-chronic liver failure (ACLF) other than AH, patients with less severe AH, or patients with non-response to corticosteroids, results were similar to those of overall analyses, both for mortality and occurrence of infection.

Conclusions

Granulocyte colony-stimulating factor therapy may improve the prognosis of patients with severe AH. However, owing to the high heterogeneity observed in the overall analysis caused by conflicting results between the Asian and European studies, G-CSF cannot currently be recommended for AH, particularly in Europe. Whether these differences can be explained by ethnic differences or disparities in patient selection and disease severity remains unclear.

Lay summary

The main finding of this meta-analysis is that the use of granulocyte colony-stimulating factor (G-CSF) is associated with a mortality reduction of more than 70% at 3 months amongst patients with alcoholic hepatitis (AH) compared with controls who did not receive this therapy. However, owing to the high heterogeneity observed in the overall analysis caused by conflicting results between the Asian and European studies, G-CSF cannot currently be recommended for patients with AH, particularly in Europe. Whether these differences can be explained by ethnic differences or disparities in patient selection and disease severity remains unclear.

•

This meta-analysis reports pooled data from 7 studies on the use of G-CSF in patients with alcoholic hepatitis.

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The favourable effect of G-CSF was only encountered in Asian not European studies.

•

Additional data are needed to clarify the usefulness of G-CSF in severe alcoholic hepatitis, particularly in Europe.

The immunological roles in acute-on-chronic liver failure: An update

BACKGROUND

Acute-on-chronic liver failure (ACLF) refers to the acute deterioration of liver function that occurs in patients with chronic liver disease. ACLF is characterized by acute decompensation, organ failure and high short-term mortality. Numerous studies have been conducted and remarkable progress has been made regarding the pathophysiology and pathogenesis of this disease in the last decade. The present review was to summarize the advances in this field.

DATA SOURCES

A comprehensive search in PubMed and EMBASE was conducted using the medical subject words "acute-on-chronic liver failure", "ACLF", "pathogenesis", "predictors", and "immunotherapy" combined with free text terms such as "systemic inflammation" and "immune paralysis". Relevant papers published before October 31, 2018, were included.

RESULTS

ACLF has two marked pathophysiological features, namely, excessive systemic inflammation and susceptibility to infection. The systemic inflammation is mainly manifested by a significant increase in the levels of plasma pro-inflammatory factors, leukocyte count and C-reactive protein. The underlying mechanisms are unclear and may be associated with decreased immune inhibitory cells, abnormal expression of cell surface molecules and intracellular regulatory pathways in immune cells and increased damage-associated molecular patterns in circulation. However, the main cause of susceptibility to infection is immune paralysis. Immunological paralysis is characterized by an attenuated activity of immune cells. The mechanisms are related to elevations of immune inhibitory cells and the concentration of plasma anti-inflammatory molecules. Some immune biological indicators, such as soluble CD163, are used to explore the pathogenesis and prognosis of the disease, and some immunotherapies, such as glucocorticoids and granulocyte colony-stimulating factor, are effective on ACLF.

CONCLUSIONS

Overwhelming systemic inflammation and susceptibility to infection are two key features of ACLF. A better understanding of the state of a patient's immune system will help to guide immunotherapy for ACLF.

Therapeutic effect of human umbilical cord blood mesenchymal stem cells combined with G-CSF on rats with acute liver failure

Human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) have been used to facilitate healing in animal models of liver injury, while granulocyte colony-stimulating factor (G-CSF) has been shown to stimulate stem cell mobilization and these cells may contribute to liver repair. hUCB-MSCs were characterized by flow cytometry, and transplanted into rats with d-galactosamine (D-GalN)/lipopolysaccharides (LPS)-induced acute liver failure (ALF) together with granulocyte colony-stimulating factor (G-CSF). Liver function, oxidative stress and pro-inflammatory cytokines expressions were examined using enzyme-linked immunosorbent assay (ELISA). Hematoxylin-eosin (HE) staining was used to observe the morphological changes. Apoptosis was investigated by terminal dUTP nick end labeling (TUNEL) staining. Bromodeoxyuridine (BrdU) cell proliferation assay was analyzed by immunofluorescence and immunohistochemistry. In the results, cultured hUCB-MSCs displayed proliferation and adipogenic and osteogenic differentiation potentials. hUCB-MSCs in combination with G-CSF significantly attenuated ALF-induced liver function injury. Furthermore, hUCB-MSCs and G-CSF treatment remarkably suppressed the secretions of pro-inflammatory cytokines and MDA activation induced by ALF. In addition, inflammation, lesions and cell apoptosis in liver tissues were obviously ameliorated by application of hUCB-MSCs and G-CSF. In conclusion, hUCB-MSCs, alone or co-treatment with G-CSF could ameliorate ALF in rats by inhibiting liver function injury, production of pro-inflammatory cytokines, oxidative stress, and liver cell apoptosis.

Altered PGE2-EP2 is associated with an excessive immune response in HBV-related acute-on-chronic liver failure

Background and aims

Prostaglandin E receptor 2 (EP2) is an immune modulatory molecule that regulates the balance of immunity. Here we investigated the role of EP2 in immune dysregulation in patients with acute-on-chronic liver failure (ACLF).

Methods

Plasma Progstaglandin E2 (PGE2) levels and EP2 expression on immune cells were determined in blood samples collected from patients with chronic hepatitis B related ACLF(HB-ACLF), patients with chronic hepatitis B (CHB), acute decompensated cirrhosis without ACLF (AD) and healthy controls (HC). Cytokine production, bacterial phagocytosis and reactive oxygen species (ROS) production were detected to explore the role of EP2 in regulating immune cell functions.

Results

The plasma PGE2 levels were increased and EP2 expression on CD8⁺ T cells was decreased in HB-ACLF compared with those in controls. The levels of PGE2 and EP2 were associated with systemic inflammation and disease severity. Small molecular chemicals against EP2 increased both cytokine secretion in PBMCs and ROS production in neutrophils and monocytes, but decreased monocytic phagocytosis. By contrast, an EP2-selective agonist reduced the production of a series of cytokines in PBMCs, but increased G-CSF.

Conclusion

Altered PGE2-EP2 augmented the excessive inflammation of innate and adaptive immune cells in response to LPS or E. coli in HB-ACLF. EP2 might be a new potential target for HB-ACLF treatment.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1844-0) contains supplementary material, which is available to authorized users.

Human Placenta Hydrolysate Promotes Liver Regeneration via Activation of the Cytokine/Growth Factor-Mediated Pathway and Anti-oxidative Effect

Liver regeneration is a very complex process and is regulated by several cytokines and growth factors. It is also known that liver transplantation and the regeneration process cause massive oxidative stress, which interferes with liver regeneration. The placenta is known to contain various physiologically active ingredients such as cytokines, growth factors, and amino acids. In particular, human placenta hydrolysate (hPH) has been found to contain many amino acids. Most of the growth factors found in the placenta are known to be closely related to liver regeneration. Therefore, in this study, we investigated whether hPH is effective in promoting liver regeneration in rats undergoing partial hepatectomy. We confirmed that cell proliferation was significantly increased in HepG2 and human primary cells. Hepatocyte proliferation was also promoted in partial hepatectomized rats by hPH treatment. hPH increased liver regeneration rate, double nucleic cell ratio, mitotic cell ratio, proliferating cell nuclear antigen (PCNA), and Ki-67 positive cells in vivo as well as interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), and hepatocyte growth factor (HGF). Moreover, Kupffer cells secreting IL-6 and TNF-α were activated by hPH treatment. In addition, hPH reduced thiobarbituric acid reactive substances (TBARs) and significantly increased glutathione (GSH), glutathione peroxidase (GPx), and superoxide dismutase (SOD). Taken together, these results suggest that hPH promotes liver regeneration by activating cytokines and growth factors associated with liver regeneration and eliminating oxidative stress.

Acute-on-chronic liver failure: Pathogenesis, prognostic factors and management

Acute-on-chronic liver failure (ACLF) is increasingly recognized as a complex syndrome that is reversible in many cases. It is characterized by an acute deterioration of liver function in the background of a pre-existing chronic liver disease often associated with a high short-term mortality rate. Organ failure (OF) is always associated, and plays a key role in determining the course, and the outcome of the disease. The definition of ACLF remains controversial due to its overall ambiguity, with several disparate criteria among various associations dedicated to the study of liver diseases. Although the precise pathogenesis needs to be clarified, it appears that an altered host response to injury might be a contributing factor caused by immune dysfunction, ultimately leading to a pro-inflammatory status, and eventually to OF. The PIRO concept (Predisposition, Insult, Response and Organ Failure) has been proposed to better approach the underlying mechanisms. It is accepted that ACLF is a different and specific form of liver failure, where a precipitating event is always involved, even though it cannot always be ascertained. According to several studies, infections and active alcoholism often trigger ACLF. Viral hepatitis, gastrointestinal haemorrhage, or drug induced liver injury, which can also provoke the syndrome. This review mainly focuses on the physiopathology and prognostic aspects. We believe these features are essential to further understanding and providing the rationale for improveddisease management strategies.

Immunotherapy in the treatment and prevention of infection in acute-on-chronic liver failure

Chronic liver disease, depicted by gradual destruction and fibrosis of the liver, is a condition with high and probably increasing prevalence worldwide. Its deterioration, acute-on-chronic liver failure (ACLF), is characterized by an in-hospital mortality of up to 65%. Infectious complications are the main precipitants eliciting ACLF and concurrently the main cause of death from ACLF. Patients have a marked susceptibility to bacterial infections, which is thought to arise a consequence of an inadequate immune response to microbial challenge, termed immuneparesis. The pathophysiologic mechanisms remain poorly understood. Treatments aimed at restoring the patients' immune function may prevent onset of ACLF and death from secondary infections. A number of drugs approved for patients with liver disease bear immunomodulatory potential such as albumin, glucocorticoids, N-acetylcysteine. Specific targets have been defined that may lead to development of new immunotherapeutic agents. Here, we summarize the pathophysiology of immuneparesis in ACLF and drug candidates to restore immune function and improve survival in the future.