Regulatory T cells and IFN-?-producing Th1 cells play a critical role in the pathogenesis of Sjögren's Syndrome
Sjogren's Disease (SjD) is an autoimmune disorder characterized by progressive salivary and lacrimal gland dysfunction, inflammation, and destruction, and extra glandular manifestations. The etiology and pathophysiology of SjD are incompletely understood. Regulatory T (Treg) cells are critical for immunological tolerance and although Treg abnormalities have been implicated in the pathogenesis of several autoimmune diseases, their role in SjD remains ambiguous.  We here show that Stim1fl/flStim2fl/flFoxp3-Cre (Stim1/Stim2 Foxp3cre) mice develop a SjD-like phenotype, including severe sialadenitis with hyposalivation, lacrimal gland (LG) inflammation with dry eye and corneal damage, increased anti-Ro and anti-La autoantibody levels and interstitial lung disease. At the cellular level, salivary gland inflammation in Stim1/2Foxp3 mice is characterized by infiltration with CD4+ and CD8+ T cells, which is dominated by a T helper (Th) 1 and Th2 immune response. The changes in gene expression in SGs of mice correlate strongly with transcriptional and epigenetic dysregulation found in SjD patients. Our findings in Stim1/Stim2 Foxp3cre mice provide new evidence for a critical role of Treg cells and IFN? producing Th1 cells in mediating SjD progression. Overall design: Whole submandibular glands (SMG) of unstimulated Stim1/Stim2 Foxp3cre and Cre negative littermate control mice were isolated. Differential gene expression between the two conditions was determined by bulk RNA sequencing.