Expression of interleukin-18 in primary Sjögren syndrome and its potential mechanisms with disease: A systematic review and meta-analysis.

BACKGROUND

Interleukin-18 (IL-18), an IL-1 family cytokine with potent ability to induce interferon gamma production and enhance Th1 response, was elevated in a group of autoimmune diseases including primary Sjögren syndrome (pSS). IL-18 dysregulation can contribute to the pathogenesis of these disorders by exerting function in innate and adaptive immunity. This study is aimed at comparing the level of IL-18 in pSS patients and explored the association between IL-18 and pSS.

METHODS

Six databases, including PubMed, Web of Science, Embase, Ovid Medline, Scopus and China National Knowledge Infrastructure, were searched. The quality of the included studies was assessed using the Newcastle-Ottawa Scale criteria. We analyzed IL-18 concentrations in the serum and tear of pSS patients and healthy controls (HCs), and review the potential mechanism between IL-18 and pSS.

RESULTS

Eleven articles were included in this study, which reported IL-18 levels in serum and tear of pSS patients and HCs. IL-18 levels in pSS patients were significantly higher than those in HCs (standard mean difference = 1.28, 95% confidence interval 0.75-1.82, P < .001), with substantial heterogeneity (I2 = 90%, P < .001) among the studies. The level of IL-18 in serum was analyzed separately and was also higher than those in HCs (standard mean difference = 1.28, 95% confidence interval 0.68-1.88, P < .001), with significant heterogeneity (I2 = 91%, P < .001). Apart from that, the potential pathogenesis of pSS was concluded comprehensively.

CONCLUSION

IL-18 abundance was evidently elevated in pSS patients and can thus likely be used as a reliable biomarker to monitor and track the progression of pSS, and further to become a good target for treatment of pSS patient.