Histological, ultrastructural, and single-cell profiling reveal immune-mediated remodeling in gallbladder inflammation.

Gallbladder inflammation comprises distinct pathological entities, including acute, neutrophil-dominated injury and chronic, fibrotic remodeling. This study aimed to define the cellular and structural programs that characterize these two inflammatory states and link epithelial, immune, and stromal alterations. Tissue and blood samples from forty-one patients, including twelve with acute cholecystitis and twenty-nine with chronic cholelithiasis, were analyzed using histopathology, immunohistochemistry, transmission electron microscopy, targeted cytokine expression analysis, and single-cell RNA sequencing of immune-enriched suspensions. Acute cholecystitis showed epithelial disruption, edema, and dense infiltration by neutrophils and macrophages, including an increased density of CD163+ macrophages, accompanied by elevated systemic inflammation. Chronic cholelithiasis displayed preserved epithelial continuity, fibrosis, glandular remodeling, and reduced immune-cell density. Ultrastructural analysis revealed abundant mucin granules and intact junctions in acute inflammation, contrasting with mucin depletion and dense-body accumulation in chronic disease. Single-cell transcriptomic analysis identified twelve immune and stromal populations, showing contrasting immune-stromal configurations: pro-inflammatory myeloid and cytotoxic T cells dominated in acute inflammation, whereas macrophage-B-cell-fibroblast networks were enriched in chronic cholelithiasis, reflecting adaptive and fibrotic remodeling rather than a temporal transition. This study defines distinct but coordinated immune-stromal programs underlying human gallbladder inflammation and provides a cellular framework for understanding condition-specific mechanisms of acute and chronic disease.