Association of Inflammatory Cytokine Levels with Extra Glandular Manifestations, Fatigue, and Disease Activity in Primary Sjögren’s Syndrome in Saudi Patients: A Cross-Sectional Study

Abstract

Background: Primary Sjögren’s syndrome (pSS) is an autoimmune disease that can cause fatigue and extraglandular manifestations (EGMs). pSS is associated with cytokine network dysregulation, which may be related to the immune-mediated destruction of exocrine glands. Objective: We determined cytokine levels and their relationship to EGMs, the European League Against Rheumatism (EULAR) Sjögren’s syndrome disease activity index (ESSDAI), and fatigue in Saudi patients with pSS. Methods: This study was a cross-sectional, single-center study. We included forty-one patients and 71 controls. Serum samples were collected from random healthy people and pSS patients who were followed in the rheumatology and pulmonary clinics of King Saud University Medical City in Riyadh, Saudi Arabia. Levels of the frequently studied cytokines were measured using Luminex xMAP technology. Each ESSDAI score and EGM were recorded, and the Arabic version of the fatigue severity scale (FSS) was applied to assess fatigue. The main outcome measures were cytokine levels in pSS Saudi patients using/not using immune-suppressive medications (ISMs). Results: Thirty-six (87.8%) patients had one or more EGMs, and the mean ESSDAI score was 9.95 ± 7.73. There was a significant decrease in TNFα and IL-21 levels in the pSS group compared to those in the control group (p = 0.034 and p < 0.001, respectively), whereas IL-12 levels were significantly elevated in the pSS group (p = 0.002). Cytokine levels in patients who used ISMs were the same as those in patients who did not use medications. Decreased IL-1β (p = 0.014), IL-2 (p = 0.035), IL-6 (p = 0.014), and IL-35 (p = 0.010) levels were observed in patients who had EGMs. Patients who had low disease activity exhibited low IL-10 (p = 0.018) and high IFN-α (p = 0.049), IFN-β (p = 0.049), IL-1β (p = 0.006), and IL-35 (p = 0.032) levels compared to patients with high disease activity. A negative association between a positive fatigue score and IL-1β (p = 0.010), IL-2 (p = 0.037), IFN-α (p = 0.025), TNFα (p = 0.030), IL-17 (p = 0.029), IL-12 (p = 0.046), and IL-21 (p = 0.005) levels was found. Conclusions: Cytokine profiles correlate with EGMs, ESSDAI, and fatigue. Patients with controlled disease activity have a normal cytokine profile that is similar to that of controls.

Pulmonary Involvement in Sjögren’s Syndrome: Correlations with Biomarkers of Activity and High-Resolution Computer Tomography Findings

“…The strongest positive correlation was identified upon analyzing the relation between IL-8 and the Warrick score (r = 0.9156, p < 0.00001), signifying that high levels of IL-8 are indicative of a more severe and extensive pulmonary involvement. This correlation between cytokine levels and disease activity has also been reported by other scientific papers, though IL-8 was not the focus of the aforementioned publications [28,29], underlining the need for further research in regard to utilizing interleukins as a means for monitoring disease activity in relation to the lung, as well as a more in-depth delving into the etiological mechanisms of SS.…”