Salivary cytokine profiles in primary Sjögren's syndrome differ from those in non-sjögren sicca in terms of TNF-α levels and Th-1/Th-2 ratios

Abstract

Objective To compare salivary cytokine profiles in patients with primary Sjogren's syndrome (pSS), non-SS sicca controls, and non-sicca controls, and to investigate whether cytokine levels are correlated with clinical parameters of ASS patients. Methods Un-stimulated whole saliva samples were obtained from pSS patients (n=30) classified according to the criteria of the American European Consensus Group. Age- and gender-matched non-SS sicca patients (n=30) and non-sicca subjects (n=25) served as controls. Salivary IFN-gamma. TNF-alpha, IL-1, IL-4, IL-6, IL-10, IL-12p40, and IL-17 levels were measured using a multiplex Luminex(R) bead-based assay. Results pSS patients and non-SS sicca controls had significantly lower salivary,flow rates (SFRs) than non-sicca controls, and pSS patients showed a more profound decrease than non-SS sicca controls. In addition, pSS patients and non-SS sicca controls had higher levels of IFN-gamma, TNF-alpha, IL-1, IL-4, IL-10, IL-12p40, and IL-17 in their saliva than non-sicca controls. Salivary TNF-alpha levels were higher in pSS patients than in non-SS sicca controls. Th-1/Th-2 ratios, represented by INF-gamma/IL-4 and TNF-alpha/IL-4 ratios, were significantly higher in pSS patients than in non-SS sicca controls. SFR was found to be correlated with INF-gamma/IL-4 ratio (r=0.411 p=0.024), and focus score to be correlated with TNF-alpha/IL-4 ratio (r=0.581, p=0.023) in pSS patients. Conclusion Th-1, Th-2, and Th17 cytokine levels were found to be elevated in the saliva of pSS patients compared with non-sicca controls. However, considerable overlap was observed between the salivary cytokine levels of pSS patients and of non-SS sicca controls. The features that most differentiated pSS and non-SS sicca were higher TNF-alpha levels and Th-1/Th-2 ratios. Th-1/Th-2 ratio was also found to be correlated with the clinical parameters of pSS.