Abnormal Innate Immunity in Acute-on-Chronic Liver Failure: Immunotargets for Therapeutics

Chishao - Fuzi herbal pair restore the macrophage M1/M2 balance in acute-on-chronic liver failure

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional herbal pair Paeoniae Radix Rubra (roots of Paeonia lactiflora Pall., Chishao in Chinese) and Aconiti Lateralis Radix Praeparata (lateral roots of Aconitum carmichaelii Debeaux, Fuzi in Chinese) are widely used for the treatment of liver diseases, demonstrating clinical efficacy against acute-on-chronic liver failure (ACLF). As the core drug pair representing the "clearing method" and "warming method" in traditional Chinese medicine (TCM), they align with the TCM syndromic characteristics of ACLF, characterized by a mixture of deficiencies and realities. However, the molecular mechanisms underlying the anti-ACLF effects of Chishao - Fuzi herbal pair remain unclear.

AIM OF THE STUDY

To reveal the immunoinflammatory status of patients with hepatitis B virus-related ACLF (HBV-ACLF) based on macrophage polarization and to explore the mechanism of action of Chishao - Fuzi herbal pair in regulating macrophage polarization against ACLF.

MATERIALS AND METHODS

Peripheral blood samples were prospectively obtained from patients with HBV-ACLF, patients with chronic hepatitis B (CHB) in the immunoactive phase and healthy individuals. Flow cytometry, qRT-qPCR, and ELISA were used to reveal the activation status of monocyte-macrophages and the expression differences in related cytokines in the peripheral blood of patients with HBV-ACLF. Then, an ACLF rat model and a macrophage inflammation model in vitro were established. Hematoxylin-eosin staining, immunohistochemical staining, transmission electron microscopy, flow cytometry, western blotting, RT-qPCR, and ELISA were used to observe changes in the expression of M1/M2 macrophage markers and related inflammatory factors after Chishao - Fuzi herbal pair intervention, both in vivo and in vitro.

RESULTS

Patients with HBV-ACLF exhibited an imbalance in M1/M2 macrophage polarization, showing a tendency to activate M1 macrophages with high expression of CD86 and iNOS. This imbalance led to an increase in relevant pro-inflammatory factors (IL-1β, IL-6, TNF-α) and a decrease in anti-inflammatory factors (IL-10, TGF-β, VEGF), exacerbating the uncontrolled immune-inflammatory response. Chishao - Fuzi herbal pair intervention improved liver function, coagulation function, and histopathological injury in ACLF rats. It also partially ameliorated endotoxemia and inflammatory injury in ACLF. The mechanism was to restore the immune-inflammatory imbalance and prevent the exacerbation of inflammatory response to liver failure by promoting macrophage polarization toward M2 anti-inflammatory direction, inhibiting M1 macrophage activation, and increasing the levels of anti-inflammatory factors and decreasing pro-inflammatory factors.

CONCLUSION

Chishao - Fuzi herbal pair can reduce the systemic inflammatory burden of liver failure by modulating macrophage polarization and restoring ACLF immune-inflammatory imbalance. This study provides new perspectives and strategies for studying HBV-ACLF immune reconstitution and inflammatory response control.

Monomeric C-reactive protein is associated with severity and prognosis of decompensated hepatitis B cirrhosis

C-reactive protein (CRP) is an acute-phase protein produced by the liver in response to infection and during chronic inflammatory disorders. Systemic inflammation is a major driver of cirrhosis progression from the compensated to the decompensated stage. Previous studies have shown that pentameric CRP (pCRP) to be a weak predictor of disease severity and prognosis in patients with decompensated hepatitis B cirrhosis, with it being only helpful for identifying patients with a higher short-term risk of death under certain conditions. Accumulating evidence indicates that pCRP dissociates to and acts primarily as the monomeric conformation (mCRP) at inflammatory loci, suggesting that mCRP may be a potentially superior disease marker with higher specificity and relevance to pathogenesis. However, it is unknown whether mCRP and anti-mCRP autoantibodies are associated with disease severity, or progression in decompensated hepatitis B cirrhosis. In this study, we evaluated the serum levels of mCRP and anti-mCRP autoantibodies in patients with decompensated cirrhosis of hepatitis B and their association with disease severity and theoretical prognosis. The results showed that patients with high mCRP and anti-mCRP autoantibody levels had more severe liver damage and that coagulation function was worse in patients with high anti-mCRP autoantibodies. Analysis of the correlation between pCRP, mCRP and anti-mCRP autoantibody levels with Model for End-Stage Liver Disease (MELD), Albumin-Bilirubin (ALBI), and Child-Turcotte-Pugh (CTP) prognostic scores showed that mCRP was the most strongly correlated with MELD score, followed by anti-mCRP autoantibodies; conversely, pCRP was not significantly correlated with prognostic score. Therefore, mCRP and anti-mCRP autoantibodies may be more advantageous clinical indicators than pCRP for evaluating the pathological state of decompensated hepatitis B cirrhosis.

The high level of IL-1β in the serum of ACLF patients induces increased IL-8 expression in hUC-MSCs and reduces the efficacy of hUC-MSCs in liver failure

BACKGROUND

Stem cells play a therapeutic role mainly through immunoregulation. However, the immunomodulatory function of stem cells may be affected by inflammation-related factors in patients' serum. Therefore, this study aims to investigate the possible mechanism by which acute-on-chronic liver failure (ACLF) patient serum influences the efficacy of hUC-MSCs.

METHODS

The serum of surviving and dead ACLF patients was collected to culture hUC-MSCs in vitro, and the hUC-MSCs cultured in the serum of ACLF patients were used to treat acute liver failure (ALF) rats. The therapeutic effect on the rats was evaluated by a survival curve, the transaminase level and liver histopathology. The expression of cytokines in hUC-MSCs was detected by Q-PCR and ELISA.

RESULTS

Serum pretreatment reduced the therapeutic effect of hUC-MSCs on ALF, especially pretreatment in the serum from dead ACLF patients. After hUC-MSCs were cultured in the serum of surviving or dead ACLF patients, the most differentially expressed factor was IL-8. Interfering with the expression of IL-8 in hUC-MSCs can improve the therapeutic effect of hUC-MSCs on ALF. The high level of IL-1β in the serum of dead ACLF patients causes the increased expression of IL-8 in hUC-MSCs through the activation of the NF-κB signaling pathway. Meanwhile, we found that the neutralizing IL-1β in serum from dead ACLF patients can improve the therapeutic effect of hUC-MSCs on ALF.

CONCLUSION

The high level of IL-1β in ACLF serum can promote the expression of IL-8 in hUC-MSCs through the NF-κB signaling pathway, thus reducing the effect of hUC-MSCs on ALF.

Utility of neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in predicting acute-on-chronic liver failure survival

This study explored the predictive value of the monocyte-to-lymphocyte ratio (MLR) and platelet-lymphocyte ratio (PLR) in patients with acute-on-chronic liver failure (ACLF). A retrospective analysis was carried out on 40 patients with ACLF from January 2018 and August 2019 in our hospital. The patient's clinical information during hospitalization was collected, and their survivals were followed for 3 months. MLR and PLR values of patients were compared, and the correlation between liver function indicators and prognosis was analyzed. We observed that MLR levels in the survival and death groups were 0.521 (0.311, 0.827) and 0.741 (0.442, 1.121), respectively. MLR levels were markedly enhanced in the death group compared to the survival group (P = 0.021). The receiver operating characteristic curve (ROC) exhibited that the area under the ROC curve and 95% confidence interval for the survival group was 0.641 (0.528-0.757). Survival analysis demonstrated that the 3-month survival of the high MLR group was markedly lower than that of the low MLR group (P = 0.001). Multivariate regression exposed that MLR and PLR were independent prognostic factors for ACLF. MLR and PLR could be prospective prognosticative markers of ACLF.

Definition, diagnosis and epidemiology of acute-on-chronic liver failure

This narrative review addresses the definition of acute-on-chronic liver failure, a condition associated with high short-term mortality in patients with chronic liver disease and/or cirrhosis. We provide two major points of view: the East and the West perspective. Both definitions vary regarding the underlying patient population and organ failure(s) definition. Nevertheless, all the definitions have their clinical utility: from the core concept of having the "liver" as a conditio sine qua non, the syndrome cannot exist (Asian Pacific Association for the Study of the Liver); a data-driven, robust definition (European Association for the Study of the Liver); a bedside tool that can quickly identify patients at high risk of dying (North American Consortium for the Study of End-stage Liver Disease [NACSELD]). In each section, we provide the overall definitions, the criteria of organ failure(s), and some epidemiological data illustrating how these apply in each area of the world.

Pediatric acute liver failure in Saudi Arabia: prognostic indicators, outcomes and the role of genetic testing

OBJECTIVE

The objective of this study was to determine the etiologies, outcomes, prognostic indicators and the role of genetic testing in children with acute liver failure (ALF).

METHODS

This retrospective study included 46 patients with pediatric acute liver failure (PALF) according to the PALF study group definition, admitted to King Fahad Specialist Hospital-Dammam, Saudi Arabia, between January 2014 and December 2021. Patients who survived with supportive therapy were designated as the recovery group, whereas those who died or underwent liver transplantation were designated as the death/transplant group.

RESULTS

There were 26 (56.5%) patients in the recovery group and 20 (43.5%) patients in the death/transplant group. Four patients (8.7%) underwent liver transplantation. After indeterminate causes (45.6%), genetic-metabolic diseases and drug-induced liver injury (DILI) were the most common cause with 15.2 and 13%, respectively. Genetic testing had a high yield of (6/31) in identifying monogenic disease associated with ALF. Younger age, lower Glasgow Coma Scale and higher international normalized ratio (INR) on admission were predictors for poor prognosis. The death/transplant group had longer intensive care unit stay ( P  < 0.001), and on admission they had more advanced hepatic encephalopathy ( P  < 0.005), more prolonged prothrombin time ( P  < 0.001), higher lactate ( P  < 0.006), higher total and direct bilirubin ( P  < 0.008) and ( P  < 0.001), respectively.

CONCLUSION

Genetic, metabolic and DILI causes constituted the most common cause of PALF after indeterminate causes. The use of genetic testing can improve diagnostic rates in special cases, but we could not assess the effect of genetic testing on prognosis. The overall survival rate in our study was 65.2%. Younger age, higher admission INR and lower Glasgow coma scale were indicators of poor prognosis.

The progress to establish optimal animal models for the study of acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) defines a complicated and multifaceted syndrome characterized by acute liver dysfunction following an acute insult on the basis of chronic liver diseases. It is usually concurrent with bacterial infection and multi-organ failure resulting in high short-term mortality. Based on the cohort studies in ACLF worldwide, the clinical course of ACLF was demonstrated to comprise three major stages including chronic liver injury, acute hepatic/extrahepatic insult, and systemic inflammatory response caused by over-reactive immune system especially bacterial infection. However, due to the lack of optimal experimental animal models for ACLF, the progress of basic study on ACLF is limping. Though several experimental ACLF models were established, none of them can recapitulate and simulate the whole pathological process of ACLF patients. Recently, we have developed a novel mouse model for ACLF combining chronic liver injury [injection of carbon tetrachloride (CCl₄) for 8 weeks], acute hepatic insult (injection of a double dose CCl₄), and bacterial infection (intraperitoneal injection of Klebsiella pneumoniae), which could recapitulate the major clinical features of patients with ACLF worsened by bacterial infection.

Blood concentrations of mediators released from activated neutrophils are related to the severity of alcohol-induced liver damage

BACKGROUND

Immune dysregulation and neutrophil infiltration are hallmarks of alcohol-related liver disease (ALD). Our objective was to evaluate the blood profile of neutrophil-derived mediators [neutrophil elastase (NE), myeloperoxidase (MPO), alpha1-antitrypsin (A1AT)], and their potential relevance in ALD.

METHODS

62 patients with ALD /47 males, and 15 females, aged 49,2 ± 9,9/ were prospectively recruited and distributed according to their 1/ gender, 2/ severity of liver dysfunction (by Child-Turcotte-Pugh, MELD scores, and mDF) 3/ presence of complications of ALD complications, and followed for 90 days. 24 age- and sex-matched healthy volunteers served as the control group. Neutrophil-derived biomarkers were quantified using enzyme-linked immunosorbent assays (ELISAs).

RESULTS

Blood concentrations of MPO and NE were significantly higher in ALD patients in comparison with controls. A1AT levels were not different. There were no gender-related differences in the studied biomarker levels. Both NE and MPO correlated with routine markers of inflammation, while NE with MELD and mDF scores. Patients with a severe ALD course i.e. MELD>20 or mDF>32, presented with significantly higher NE blood concentrations.

CONCLUSIONS

Our results point out the critical role of neutrophils in the pathogenesis of ALD. NE and MPO correlated with the intensity of inflammation, and NE was related to the severity of liver dysfunction.

The immunological function of CXCR2 in the liver during sepsis

Background

The chemokine receptor CXCR2 and its ligands, especially CXCL8, are crucial mediators for the progression of liver inflammation and liver failure in sepsis. Neutrophils have the highest CXCR2 expression in mice and humans, and their activation via CXCL8 facilitates their migration to the inflamed liver for the clearance of the pathogens and, in turn, the inflammation.

Main body

In sepsis, the inflammatory insult causes extensive neutrophil migration to the liver that overwhelms the immune response. To compensate for the strong receptor activation, CXCR2 desensitizes, incapacitating the immune cells to efficiently clear pathogens, causing further life-threatening liver damage and uncontrolled pathogen spread.

Conclusion

CXCR2 function during infection strongly depends on the expressing cell type. It signals pro- and anti-inflammatory effects that may prompt novel cell-type-specific CXCR2-directed therapeutics.

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.

The role of platelet mediated thromboinflammation in acute liver injury

Acute liver injuries have wide and varied etiologies and they occur both in patients with and without pre-existent chronic liver disease. Whilst the pathophysiological mechanisms remain distinct, both acute and acute-on-chronic liver injury is typified by deranged serum transaminase levels and if severe or persistent can result in liver failure manifest by a combination of jaundice, coagulopathy and encephalopathy. It is well established that platelets exhibit diverse functions as immune cells and are active participants in inflammation through processes including immunothrombosis or thromboinflammation. Growing evidence suggests platelets play a dualistic role in liver inflammation, shaping the immune response through direct interactions and release of soluble mediators modulating function of liver sinusoidal endothelial cells, stromal cells as well as migrating and tissue-resident leucocytes. Elucidating the pathways involved in initiation, propagation and resolution of the immune response are of interest to identify therapeutic targets. In this review the provocative role of platelets is outlined, highlighting beneficial and detrimental effects in a spatial, temporal and disease-specific manner.

Upregulation of microRNA-125b-5p alleviates acute liver failure by regulating the Keap1/Nrf2/HO-1 pathway

Background

Acute liver failure (ALF) and acute-on-chronic liver failure (ACLF) are the two most common subtypes of liver failure. They are both life-threatening clinical problems with high short-term mortality. Although liver transplantation is an effective therapeutic, its application is limited due to the shortage of donor organs. Given that both ACLF and ALF are driven by excessive inflammation in the initial stage, molecules targeting inflammation may benefit the two conditions. MicroRNAs (miRNAs) are a group of small endogenous noncoding interfering RNA molecules. Regulation of miRNAs related to inflammation may serve as promising interventions for the treatment of liver failure.

Aims

To explore the role and mechanism of miR-125b-5p in the development of liver failure.

Methods

Six human liver tissues were categorized into HBV-non-ACLF and HBV-ACLF groups. Differentially expressed miRNAs (DE-miRNAs) were screened and identified through high-throughput sequencing analysis. Among these DE-miRNAs, miR-125b-5p was selected for further study of its role and mechanism in lipopolysaccharide (LPS)/D-galactosamine (D-GalN) -challenged Huh7 cells and mice in vitro and in vivo.

Results

A total of 75 DE-miRNAs were obtained. Of these DE-miRNAs, miR-125b-5p was the focus of further investigation based on our previous findings and preliminary results. We preliminarily observed that the levels of miR-125b-5p were lower in the HBV-ACLF group than in the HBV-non-ACLF group. Meanwhile, LPS/D-GalN-challenged mice and Huh7 cells both showed decreased miR-125b-5p levels when compared to their untreated control group, suggesting that miR-125b-5p may have a protective role against liver injury, regardless of ACLF or ALF. Subsequent results revealed that miR-125b-5p not only inhibited Huh7 cell apoptosis in vitro but also relieved mouse ALF in vivo with evidence of improved liver histology, decreased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and reduced tumor necrosis factor-α (TNF-α) and IL-1β levels. Based on the results of a biological prediction website, microRNA.org, Kelch-like ECH-associated protein 1 (Keap1) was predicted to be one of the target genes of miR-125b-5p, which was verified by a dual-luciferase reporter gene assay. Western blot results in vitro and in vivo showed that miR-125b-5p could decrease the expression of Keap1 and cleaved caspase-3 while upregulating the expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1(HO-1).

Conclusion

Upregulation of miR-125b-5p can alleviate acute liver failure by regulating the Keap1/Nrf2/HO-1 pathway, and regulation of miR-125b-5p may serve as an alternative intervention for liver failure.

Identification of effective diagnostic biomarker and immune cell infiltration characteristics in acute liver failure by integrating bioinformatics analysis and machine-learning strategies

Background: To determine effective biomarkers for the diagnosis of acute liver failure (ALF) and explore the characteristics of the immune cell infiltration of ALF.

Methods: We analyzed the differentially expressed genes (DEGs) between ALF and control samples in GSE38941, GSE62029, GSE96851, GSE120652, and merged datasets. Co-expressed DEGs (co-DEGs) identified from the five datasets were analyzed for enrichment analysis. We further constructed a PPI network of co-DEGs using the STRING database. Then, we integrated the two kinds of machine-learning strategies to identify diagnostic biomarkers of top hub genes screened based on MCC and Degree methods. And the potential diagnostic performance of the biomarkers for ALF was estimated using the AUC values. Data from GSE14668, GSE74000, and GSE96851 databases was performed as external verification sets to validate the expression level of potential diagnostic biomarkers. Furthermore, we analyzed the difference in the protein level of diagnostic biomarkers between normal and ALF mice models. Finally, we used CIBERSORT to estimate relative infiltration levels of 22 immune cell subsets in ALF samples and further analyzed the relationships between the diagnostic biomarkers and infiltrated immune cells.

Results: A total of 200 co-DEGs were screened. Enrichment analyses depicted that they are highly enriched in metabolism and matrix collagen production-associated processes. The top 28 hub genes were obtained by integrating MCC and Degree methods. Then, the collagen type IV alpha 2 chain (COL4A2) was regarded as the diagnostic biomarker and showed excellent specificity and sensitivity. COL4A2 also showed a statistically significant difference and excellent diagnostic effectiveness in the verification set. In addition, there was a significant upregulation in the COL4A2 protein level in ALF mice models compared with the normal group. CIBERSORT analysis showed that activated CD4 T cells, plasma cells, macrophages, and monocytes may be implicated in the progress of ALF. In addition, COL4A2 showed different degrees of correlation with immune cells.

Conclusion: In conclusion, COL4A2 may be a diagnostic biomarker for ALF, and immune cell infiltration may have important implications for the occurrence and progression of ALF.

Soluble factors and suppressive monocytes can predict early development of sepsis in acute-on-chronic liver failure

Patients with acute-on-chronic liver failure (ACLF) have a high probability of developing systemic inflammation and sepsis due to immune dysregulation. Fifty-nine patients with ACLF (12 without and 19 with systemic inflammation, and 28 with sepsis) were serially monitored for clinical and immunological changes at baseline, 6 hours, 24 hours, day 3, and day 7 following hospitalization. Ten healthy controls were also included. At all time points, soluble plasma factors and monocyte functions were studied. Patients with ACLF and systemic inflammation showed higher interleukin (IL)-6, vascular endothelial growth factor-a, monocyte chemoattractant protein 1, and macrophage inflammatory protein 1β than patients with no systemic inflammation. Patients with ACLF with sepsis had raised (p < 0.001) levels of IL-1Ra, IL-18, and triggering receptor expressed on myeloid cells 1 (TREM1) compared to patients with ACLF-systemic inflammation. Five of the 19 (26.3%) patients with systemic inflammation developed sepsis within 48-72 hours with a rapid rise in plasma levels of IL-1Ra (1203-35,000 pg/ml), IL-18 (48-114 pg/ml), and TREM1 (1273-4865 pg/ml). Monocytes of patients with ACLF with systemic inflammation and sepsis showed reduced human leukocyte antigen-DR but increased programmed death ligand 1 (PD-L1) and T-cell immunoglobulin and mucin domain-containing protein 3 (TIM3) (p < 0.04) expression with increased ETosis by monocytes at baseline and until day 7. Conclusion: High and rising levels of plasma IL-1Ra, IL-18, TREM1 soluble factors, and increased suppressive monocytes (PDL1^+ve , TIM3^+ve ) at baseline can stratify patients with ACLF at high risk of developing sepsis within 48-72 hours of hospitalization.

Role of immune dysfunction in drug induced liver injury

Drug-induced liver injury (DILI) is one of the leading causes of liver failure and withdrawal of drugs from the market. A poor understanding of the precipitating event aetiology and mechanisms of disease progression has rendered the prediction and subsequent treatment intractable. Recent literature suggests that some drugs can alter the liver’s repair systems resulting in injury. The pathophysiology of DILI is complex, and immune dysfunction plays an important role in determining the course and severity of the disease. Immune dysfunction is influenced by the host response to drug toxicity. A deeper understanding of these processes may be beneficial in the management of DILI and aid in drug development. This review provides a structured framework presenting DILI in three progressive stages that summarize the interplay between drugs and the host defence networks.

Acute-on-Chronic Liver Failure: Pathophysiological Mechanisms and Management

Acute-on-chronic liver failure (ACLF) is a multifaceted condition with poor treatment options and high short-term mortality. ACLF can develop in patients with or without liver cirrhosis, where patients with decompensated cirrhosis display a higher risk of short-term mortality. Pathophysiological mechanisms include systemic inflammation due to bacterial and fungal infections and acute hepatic insult with drug, alcohol, and viral hepatitis. Cryptogenic factors also contribute to the development of ACLF. The clinical outcome of patients with ACLF gets further complicated by the occurrence of variceal hemorrhage, hepatorenal syndrome, hepatic encephalopathy, and systemic immune dysfunction. Regardless of the better understanding of pathophysiological mechanisms, no specific and definitive treatment is available except for liver transplantation. The recent approach of regenerative medicine using mesenchymal stem cells (MSCs) could be advantageous for the treatment of ACLF as these cells can downregulate inflammatory response by inducing antiinflammatory events and prevent hepatic damage and fibrosis by inhibiting hepatic stellate cell activation and collagen synthesis. Moreover, MSCs are involved in tissue repair by the process of liver regeneration. Considering the broad therapeutic potential of MSCs, it can serve as an alternative treatment to liver transplant in the near future, if promising results are achieved.

Increased Circulating T Follicular Helper Cells Induced via IL-12/21 in Patients With Acute on Chronic Hepatitis B Liver Failure

Objectives

T Follicular helper (Tfh) cells, recognized as a distinct CD4⁺ T cell subset, mediate the development of long-lived humoral immunity via B cell activation/differentiation. Tfh cells play an important role during hepatic viral infection, but its role in hepatitis B virus-related acute on chronic liver failure (HBV-ACLF) remains to be explored.

Materials and Methods

The frequency of Tfh cells, serum pro-inflammatory cytokine (IL-12, IL-21, IL-17 and TNF) levels and IgG/M levels were investigated in HBV-ACLF (n = 36), serious chronic hepatitis B (n = 21), moderate chronic hepatitis B patients (n = 32) and healthy control (HC) subjects (n = 10).

Results

Circulating Tfh cells were significantly increased in HBV-ACLF patients compared to other groups, correlating well with MELD score. However, the frequency of Tfh cells decreased in ameliorated HBV-ACLF patients. Furthermore, serum IL-12 and IL-21 levels were higher in HBV-ACLF patients, compared to other groups. Naïve CD4⁺ T cells from HC subjects differentiate into Tfh cells following treatment with HBV-ACLF patients’ serum, a process that can be blocked by IL-12/21 neutralizing antibodies. Tfh cells induced by HBV-ACLF patient’s serum promoted the proliferation and IgG production of B cells in vitro. Moreover, circulating CD19⁺ B cells, serum and liver IgG/M levels were significantly higher in HBV-ACLF patients, compared to other groups.

Conclusions

Our data demonstrated that there was a high frequency of Tfh cells and high levels of serum IL-12/21 in HBV-ACLF patients. Naïve CD4⁺ T cells differentiate into Tfh cells in the presence of HBV-ACLF patients’ serum rich in IL-12/21, which can be blocked by neutralizing IL-12/21 antibodies. These data may provide useful insights for both clinical and basic research in the treatment of HBV-ACLF.