STING Drives CD4⁺T Cell Differentiation via JAK-STAT Signalling in Bullous Pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disease with an increasing incidence in recent years; however, the underlying immune regulatory mechanisms remain largely unclear. As a critical signalling hub linking innate and adaptive immunity, stimulator of interferon genes (STING) has recently been implicated in the pathogenesis of various autoimmune diseases and may regulate tissue inflammation and immune homeostasis through modulation of CD4⁺ T cell responses. In this study, we found that STING expression was significantly increased in lesional skin tissues from patients with BP compared with healthy controls. Transcriptomic analysis further revealed that differentially expressed genes in peripheral blood CD4⁺ T cells from BP patients were primarily enriched in the JAK-STAT signalling pathway, T cell activation and differentiation, and type I interferon (IFN-I)-related pathways. Pharmacological inhibition of STING markedly attenuated the aberrant activation of these signalling pathways. Moreover, qRT-PCR analysis confirmed that the mRNA levels of STING1, JAK1, and CXCR5 were significantly elevated in BP patients, whereas treatment with the STING inhibitor C176 suppressed the expression of these molecules. Collectively, our findings suggest that STING may contribute to BP immunopathogenesis by regulating the JAK-STAT signalling axis and promoting abnormal CD4⁺ T cell activation and differentiation, providing new insights into the molecular mechanisms underlying BP and identifying potential therapeutic targets.