Transcriptome analysis of CCR9+, CXCR5+ and CCR9-CXCR5- Th cells in primary Sjögren's syndrome (pSS) patients and healthy controls (HC)

CCR9+ Tfh-like pathogenic T helper (Th) cells are elevated in patients with primary Sjögren’s syndrome (pSS) and indicated to play a role in pSS immunopathology. CCR9+, CXCR5+ and CCR9-CXCR5- (double negative, DN) Th cells from blood of 7 healthy controls (HC) and 7 pSS patients were FACS sorted and RNA sequencing was performed. Our aim is to delineate the CCR9+ Th cell-specific transcriptome to study the molecular dysregulation of these cells in pSS patients. Transcriptomic analysis of circulating CCR9+ Th cells reveals CCR9-specific pathways involved in effector T cell function, equally expressed in pSS patients and HC. Given the increased numbers of CCR9+ Th cells in the blood and inflamed glands of pSS patients and presence of inflammatory stimuli to activate these cells this suggests that CCR9-specific functions, such as cell recruitment upon CCL5 secretion, could significantly contribute to immunopathology in pSS. FACS sorted CCR9+, CXCR5+ and CCR9-CXCR5- Th cells from peripheral blood of n=7 pSS patients and n=7 HC were analyzed using RNA sequencing