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