Immune Landscape Changes in MASLD and the Effects of 11β‐HSD1 Inhibition Revealed by Single‐Cell Mass Cytometry

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects nearly one-fourth of the global population, yet effective diagnostics and treatments remain limited. Systemic immune dysregulation plays a key role in MASLD pathogenesis, highlighting the value of immune profiling. In this study, we used high-dimensional single-cell mass cytometry (CyTOF) to analyze peripheral blood mononuclear cells (PBMCs) from healthy donors (n = 6), MASLD patients (n = 4), and MASLD patients treated with an 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor (n = 2). PBMCs were stained with a 29-marker panel to identify 15 immune cell types and assess cytokine expression. MASLD patients showed increased CD8⁺ T cells, early NK cells, and monocytes, along with reductions in TH2, TH1, late NK, and Treg cells. Cytokine profiling revealed elevated IL-6 expression in plasmacytoid dendritic cells and late NK cells, indicating systemic inflammation. Automated clustering (PhenoGraph, UMAP) identified NK and phagocytic subsets associated with disease and treatment. Notably, 11β-HSD1 inhibition led to downregulation of pro-inflammatory cytokines (e.g., IFN-γ, IL-6) and partial restoration of immune subsets. These results offer a high-resolution view of immune alterations in MASLD and suggest that 11β-HSD1 inhibition may represent a promising immunomodulatory therapeutic strategy.