Fibroblasts in Sjögren’s Syndrome

The Sjögren’s syndrome is an autoimmune disease characterized by chronic inflammation of the exocrine glands, leading to dryness of mucosal surfaces, and often to severe systemic manifestations. Here, the immunomodulatory function of fibroblasts derived from salivary glands, a primary site affected by the Sjögren’s syndrome, is discussed. Specific subsets of these fibroblasts drive the formation of tertiary lymphoid structures, which are associated with severe disease and which constitute a risk factor for the development of lymphoma in Sjögren’s syndrome. Single cell RNA-sequencing has provided new insights into subsets of fibroblasts in inflamed salivary glands and has provided evidence for the existence of shared inflammation-associated fibroblasts across chronically inflamed tissues. These findings support the concept of targeting the fibroblast compartment in Sjögren’s syndrome and other chronic inflammatory diseases. In addition to the immunomodulatory role of fibroblasts, the interaction of the epithelium with fibroblasts is essential for salivary gland homeostasis. Fibroblasts provide essential signals for the regeneration of salivary gland epithelial cells, which is disturbed in Sjögren’s syndrome, and leading to the loss of saliva secreting cells and subsequent hyposalivation