Single-nucleus profiling reveals hepatocyte identity and immune features associated with corticosteroid response in severe alcohol-related hepatitis.
BACKGROUND & AIMS: Severe alcohol-related hepatitis (sAH) is associated with high short-term mortality. However, 30-40% of patients fail to respond to corticosteroids, the only proven pharmacological treatment. The pathophysiological mechanisms underlying sAH and the marked heterogeneity in treatment response remain incompletely understood. We aimed to define cellular changes associated with corticosteroid response in sAH and to identify baseline markers predictive of treatment outcome. METHODS: Single-nucleus RNA sequencing was performed on liver biopsies from patients with biopsy-proven sAH (n = 17), including paired baseline and day 8 biopsies in a subset of patients (n = 8). Patients were classified as corticosteroid responders (sAH-R; Lille score <0.45) or non-responders (sAH-NR; Lille score ≥0.45). Liver biopsies from patients with acute decompensation of alcohol-related cirrhosis (AD; n = 5) and healthy controls (n = 4) were included for comparison. Findings were validated using immunohistochemistry and spatial proteomics in a large multicenter validation cohort (n = 172). RESULTS: At baseline, sAH-R exhibited a significantly higher proportion of liver-infiltrating S100A8+ monocytes compared to sAH-NR, a difference that persisted at day 8. sAH livers showed a marked reduction in mature hepatocytes and an expansion of stressed and intermediate hepatocyte populations, indicating progressive loss of mature hepatocyte identity. This loss was more pronounced in sAH-NR, who also exhibited fewer cycling hepatocytes at day 8, consistent with impaired regenerative capacity. Expression of SULT2A1, a marker of mature hepatocyte identity, was significantly reduced in sAH-NR at baseline. Finally, liver biopsies with ≥50% SULT2A1-positive hepatocytes at baseline were strongly predictive of corticosteroid response. CONCLUSIONS: This study delineates distinct immune and hepatocyte changes associated with corticosteroid response in sAH. Baseline SULT2A1 expression may facilitate stratified treatment approaches in sAH. IMPACT AND IMPLICATIONS: Severe alcohol-related hepatitis (sAH) represents one of the most devastating manifestations of alcohol-related disorders. sAH is characterized by acute hepatic inflammation and high short-term mortality. Clinical management remains challenging, as corticosteroids - the only pharmacological therapy currently applied - are ineffective in a substantial proportion of patients and are associated with significant adverse effects. These limitations highlight the need for a more detailed understanding of sAH pathophysiology and for approaches that enable improved patient stratification and therapeutic decision-making. In this study, we identify distinct pre-treatment differences between corticosteroid responders and non-responders at the level of both hepatocytes and myeloid cells, providing new insight into the cellular mechanisms underlying treatment heterogeneity in sAH. Furthermore, leveraging these findings, we developed a histology-based SULT2A1 scoring system using a commercially available antibody, which predicts corticosteroid response at baseline and may support stratified treatment approaches in clinical practice.