The therapeutic mechanism of baritinib in idiopathic granulomatous mastitis treatment elucidated by single-cell RNA sequencing

The pathogenesis of idiopathic granulomatous mastitis (IGM) remains poorly understood. Based on compelling clinical evidence, we have discovered that baricitinib, a widely prescribed medication for autoimmune disorders, exhibits remarkable efficacy in alleviating the symptoms associated with IGM. To gain a more comprehensive understanding of the underlying mechanism of baricitinib in IGM, we performed single-cell RNA sequencing (scRNA-seq) analysis and observed an augmented presence of lip-macrophages and plasma cells_IGHG in patients with IGM. Our results indicated that IGM may possess autoimmune characteristics, potentially triggered by an upregulation of plasma cells. And plasma cells were undergoing class-switch recombination from IGHA to IGHG to lead to development of autoimmunity in IGM. Our data also revealed that lip-macrophages involved in maintaining breast homeostasis are associated with pathways related to phagocytosis, endocytosis, and lipid metabolism Over 50,000 cells from normal and inflamed tissue regions of five patients with idiopathic granulomatous mastitis