Publications by Year: 2026

Acute-on-chronic liver failure (ACLF) is a life-threatening condition characterized by acute hepatic decompensation, multi-organ failure, and high short-term mortality in patients with liver cirrhosis. A hallmark of ACLF is profound deterioration of the immune system, which contributes to organ-specific excessive inflammation and immune dysfunction, predisposing patients to infection and multi-organ failure. This review aims to elucidate the cellular and molecular mechanisms underlying systemic immune dysfunction in ACLF, highlighting key pathophysiological pathways and their clinical significance. We provide an overview of ACLF including its global prevalence and clinical significance, against the background of the underlying immune dysfunction in its pathogenesis. The discussion focuses on innate immune alterations, such as impaired neutrophil and monocyte phagocytosis, excessive neutrophil extracellular trap (NET) formation, and monocyte/macrophage dysfunction contributing to immuneparesis and exaggerated inflammation, respectively, which evolve in an organ-specific manner. Dysregulation of natural killer (NK) cell cytotoxicity and adaptive immune dysfunction, including changes in T cell subpopulations and B cell antibody production in ACLF, are discussed. We further dissect the emerging evidence of molecular pathways driving dysfunction of immune cells and their impaired ability to control infections in ACLF, emphasizing the roles of pathogen- and damage-associated molecular patterns (PAMPs/DAMPs), toll-like receptor (TLR) signaling, oxidative stress, mitochondrial dysfunction, epigenetic/metabolic reprogramming and immune checkpoint molecules. The review expands on immune cell communication within the immune system (innate and adaptive), with other non-parenchymal and parenchymal cells and at the inter-organ level, detailing interactions between immune cells of key organs and compartments affected during ACLF, including the liver, circulation, brain, gut and kidney. Finally, we summarize the latest preclinical and clinical findings exploring biomarkers of immune dysfunction and immunomodulatory therapeutic strategies aimed at restoring immune homeostasis in patients with ACLF.

BACKGROUND: Recurrent alcohol use is a major determinant of liver-related outcomes in patients recovering from alcohol-associated hepatitis (AH). However, the timing and predictors of return to drinking (RTD) are not well-studied.

METHODS: We analyzed alcohol use among patients with AH enrolled in two AlcHepNet multicenter studies: a Phase 2b randomized controlled trial and a prospective observational study. TimeLine FollowBack (TLFB) assessed drinking at each visit. RTD was defined as any alcohol use since the previous visit. The cumulative incidence of RTD was evaluated using the Fine-Gray method, with death as a competing risk. Factors associated with RTD were evaluated using univariate and multivariate Cox regression.

RESULTS: Among 518 patients alive at Day 28, RTD occurred in 7.7%, 21.7%, and 30.8% at 30, 90, and 180 days, respectively. Patients with moderate AH (mAH, MELD 11-19, n = 103) had a higher RTD incidence at 180 days than those with severe AH (sAH, MELD ≥20, n = 415) (44.3% vs. 27.5%; p = 0.01). RTD was associated with higher AUDIT scores, family history of alcohol use disorder (AUD), lower education, greater alcohol use at baseline, lower MELD scores, and less ascites (all p ≤ 0.01). In multivariable analysis, >20 drinking days in the prior month was associated with increased risk of RTD (HR: 3.46, 95% CI: 2.21-5.39), whereas college education or higher was protective (HR: 0.53, 95% CI: 0.32-0.88).

CONCLUSION: RTD occurred in 22% of AH patients within 90 days postrecovery, highlighting the need for early AUD interventions. Frequent drinking days at baseline and lower education were strongly linked to early RTD.

BACKGROUND: Increased circulating pro-inflammatory cytokine levels correlate with mortality in severe alcohol-associated hepatitis (AH), but their kinetics during disease progression or response to treatment remain unexplored.

OBJECTIVE: We longitudinally assessed circulating biomarkers in a severe AH cohort enrolled in a multicenter, double-blind clinical trial.

DESIGN: Eighty-nine patients with severe AH (MELD≥20) from 4 US sites were randomly assigned to treatment with IL-1receptor antagonist (IL-1Ra) + pentoxifylline + zinc (anakinra: 47) or methylprednisolone + placebo (steroid: 42). Plasma levels of 43 indicators of AH pathology (inflammation, bacterial translocation, liver regeneration, tissue remodeling, and cell-activation) were assessed on days 0, 7, 28, 90 and 180 after enrollment, and in 27 healthy controls.

RESULTS: Baseline characteristics and cytokine levels were similar between treatment groups but significantly different compared to healthy controls. Consistent with anakinra administration, day 7 IL-1Ra levels were significantly increased in the anakinra group accompanied by elevated levels of several other cytokines. IL-1β levels were increased in the steroid group on day 28. Strong correlations were observed between IL-1α and IL-17A as well as IL-1β and IL-13 both prior to and during treatment. Although the dysregulated biomarkers demonstrated improving trends in survivors, most did not normalize by day 180. Markers associated with 90-day mortality were distinct between the treatment groups with few exceptions (IL-13-absolute level; Sonic hedgehog and sTNFR-1-level change).

CONCLUSIONS: Circulating cytokine and immune biomarkers dynamically change in AH during treatment, disease progression and/or resolution. Our results highlight the importance of treatment-specific biomarkers in future clinical trials.

BACKGROUND: Cyclic GMP-AMP synthase (cGAS) catalyzes the production of cGAMP, which activates the STING-IRF3 signaling pathway. Previous investigations indicated a role for STING-IRF3 in early alcohol-associated liver disease (ALD). In this study, we examined the role of cGAS in liver damage and inflammation in early ALD.

METHODS: Wild-type (WT) or cGAS knockout (cGAS-KO) mice received a single dose of alcohol (5 g/kg), and in WT mice with or without a cGAS inhibitor, RU.521 (5 mg/kg) or 2'-3' cGAMP or control. Liver and serum were evaluated after 9 hours of alcohol administration.

RESULTS: Alcohol gavage in cGAS knockout (cGAS-KO) mice led to increased liver damage compared with WT mice. Inhibition of cGAS with the small molecule, RU.521, also resulted in increased serum alanine and aspartate aminotransferases. cGAS deficiency or inhibition made the liver susceptible to alcohol-induced apoptosis. Alcohol-fed cGAS-KO mice and WT mice treated with the cGAS inhibitor showed enhanced unfolded protein response in the liver. This was associated with elevated levels of the proinflammatory cytokines, macrophage migration inhibitory factor, CD68+ cells, Ly6G+ cells, and chemokines like lipocalin-2 and neutrophil elastase. Primary hepatocytes isolated from cGAS-KO mice displayed increased levels of cleaved caspase-3, XBP1s, and CHOP after alcohol administration as compared with WT control hepatocytes. Interestingly, restoration of cGAMP levels after cGAS inhibition improved liver damage and autophagic flux.

CONCLUSIONS: Our findings highlight that cGAS deficiency or cGAS inhibition predisposes the liver to increased damage, apoptosis, and unfolded protein response in early ALD. An increase in the proinflammatory cytokine MIF and chemokines involved in neutrophil recruitment might contribute to the increased liver damage. In summary, our findings indicate a protective role for cGAS activation in early ALD.