Single-cell analysis identifies monocyte signatures of disease activity and clinical subtypes in Behçet’s disease

This study used single-cell RNA sequencing of PBMCs from 34 Behçet’s disease patients and 12 healthy controls to characterize immune dysregulation across disease activity states and clinical phenotypes. BD was marked by expansion and activation of monocyte subsets, with strong IFN-γ, heat-shock, and antigen-presentation signatures, particularly during active disease. These inflammatory programs decreased in remission, which showed restoration of regulatory and metabolic pathways and increased type I interferon-related gene expression, suggesting a potentially protective role. Distinct monocyte signatures were also associated with vascular, ocular, and non-organ-involved BD. Overall, the study identifies monocyte-driven inflammation as a central feature of BD and highlights activity- and phenotype-specific pathways that may guide targeted therapies.