Objective. Salivary gland (SG) progenitor cells (SGPCs) maintain SG homeostasis. We have previously shown that in primary Sjogren's syndrome (pSS), SGPCs are likely to be senescent, and may underpin SG dysfunction. This study assessed the extent of senescence of cells in a SGPC niche in pSS patients' SGs, and its correlation with functional and clinical parameters.
Methods. The expression of p16 and p21 as markers of senescence in both total SG epithelium and a SGPC niche (basal striated duct cells, BSD) was examined in SGs of pSS (n = 35) , incomplete pSS (n = 1 3) (patients with some signs of pSS, but not fulfilling all classification criteria) and non-SS sicca control (n = 21) patients. This was correlated with functional and clinical parameters.
Results. pSS patient SGs contained significantly more p16(+) cells both in the epithelium in general (P
Conclusion. These findings suggest SGPC senescence may be an early feature of primary Sjogren's syndrome and may contribute to defective SG function in pSS but not to systemic disease activity.