Immune and Endothelial-Related Extracellular Vesicles Are Associated with Corticosteroid Response and Mortality in Alcohol-Associated Hepatitis

Alcohol-associated hepatitis (AH) is the most severe clinical manifestation of alcohol-associated liver disease. Corticosteroids are the only disease-specific therapy shown to improve short-term survival. Currently, no non-invasive markers are available to predict patient response to corticosteroids or long-term survival in AH. This study investigates whether surface antigens on plasma extracellular vesicles (EVs), key mediators of intercellular communication, can reflect the underlying immune dysregulation in AH and serve as prognostic markers. Patients with AH were prospectively enrolled between 2020 and 2024. Blood samples were collected before corticosteroid initiation during the first 24 h of hospitalization. EVs were characterized using nanoparticle tracking analysis, cryo-electron microscopy, and flow cytometry. Interleukin-6 (IL-6), soluble (s)CD62p, Circulating Vascular Cell Adhesion Molecule-1 (sVCAM), tumor necrosis factor receptor superfamily member 1 (TNRFS1a), and Intercellular Adhesion Molecule 1 (ICAM-1) were quantified by ELISA. Key outcome variables included response to corticosteroids and mortality. A total of 46 patients with AH and 28 healthy donors (HD) were included. EV concentration was significantly higher in AH patients than in HD (9.3 × 1011 [IQR 4–24] versus 2.4 × 1011 [IQR 2–4], p = 0.03). Specific EV antigens were associated with key clinical outcomes: CD20 and CD2 levels differed between patients with or without infections (bacterial, viral, and fungal) developed during hospitalization; CD40 and CD146 were elevated in patients who developed acute kidney injury. EVs enriched in monocyte (CD14) and T-reg (CD25) markers were associated with plasma IL-6 levels, while endothelial markers CD105 and CD146 correlated with sVCAM and sCD62p. EVs enriched in platelet (CD49e) and endothelial (CD31) markers were associated with corticosteroid response, whereas EVs enriched with endothelial (CD105 and CD146) and B lymphocyte (CD19) markers were associated with mortality. Overall, EVs enriched in endothelial and monocyte markers may represent a candidate non-invasive tool for predicting corticosteroid response and mortality in AH, aiding risk stratification and early identification of non-responders for timely transplant evaluation.