Health-related quality of life in patients with primary Sjogren's syndrome: relationship with serum levels of proinflammatory cytokines

Objective: A cross-sectional study of 30 patients with primary Sjogren's syndrome (pSS) was performed to analyse the health-related quality of life and its relationship with serum levels of macrophage-and lymphocyte-derived cytokines. Patients and methods: Health-related quality of life was evaluated using the 36-item Short Form Health Survey (SF-36). Serum levels of interleukin (IL)-1 beta, IL-6, IL-10, tumour necrosis factor (TNF)-alpha, and gamma-interferon (gamma-INF) were analysed by a sandwich immunoassay-based protein array system. Results: Each of the eight scales of the SF-36 evaluating quality of life, as well as the physical composite score (PCS) and the mental composite score (MCS), showed a decrease in pSS patients. Similarly, patients with pSS showed significantly increased concentrations of each of the five cytokines analysed, when compared with the healthy control group (n = 20). In pSS patients, a significant negative correlation was detected between serum levels of IL-6 and the PCS of the SF-36. Those patients with concentrations of IL-6 higher than those of the healthy controls showed a significantly lower score in the dimensions of bodily pain and physical functioning, and in the PCS. Conclusions: Patients with pSS showed increased levels of several macrophage-and lymphocyte-derived cytokines, indicating the existence of an immune activation state. Serum levels of one of these cytokines, IL-6, were correlated with poor quality of life in these individuals.