Association of increased serum I-309 with phenotypes, disease activity, and cytokine pattern in primary Sjögren's syndrome.

The aim of this study was to determine serum I-309 levels in primary Sjögren's syndrome (pSS) patients, as well as the association with disease phenotype, systemic activity, and T helper cell-related cytokines. A total of 58 pSS patients and 30 healthy controls (HC) were enrolled in this study. The concentrations of serum I-309, interleukin-4 (IL-4), IL-6, IL-9, IL-13, IL-17, IL-22, IL-23, tumor-necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IFN-α, and IFN-β were measured with multiplex immunoassay. The relationships between I-309 and various clinical and laboratory variables were analyzed. The serum concentrations of I-309 were significantly increased (median, IQR, 14.24, 10.99--20.35, pg/ml) in pSS patients compared with HC (median, IQR, 8.27, 6.74--9.62, pg/ml) (P < 0.001). Serum I-309 is increased in pSS, and may be associated with systemic inflammation, Th1-, Th17,- and Th9 cells, type Key Points • Serum I-309 levels are increased in pSS patients. • Increased I-309 may be associated with systemic rather than local manifestations in pSS. • Increased I-309 may be associated with Th1, Th17 and Th9 other than Th2 in pSS. • There may be close relationships between I-309 and type land type II IFNs in pSS.