Serum interleukin-۱۸ and its relationship with subclinical atherosclerosis in systemic lupus erythematosus

BACKGROUND: Interleukin-۱۸ (IL-۱۸) is a pro-inflammatory and pro-atherogenic factor, and its blood level has shown a direct correlation with atherosclerosis. We aimed to evaluate the serum IL-۱۸ level in patients with systemic lupus erythematosus (SLE) and its relationship with the intima-media thickness (IMT) of the carotid artery in these patients, as an indicator of atherosclerosis.METHODS: In this cross-sectional study, ۶۰ patients as the patient group and ۳۰ healthy volunteers as the control group [matched sex, age, and body mass index (BMI)] were selected, and their disease status and general data were gathered using the Systemic Lupus Erythematosus Disease Activity Index ۲۰۰۰ (SLEDAI-۲K) form. A blood sample was also obtained from all participants to determine the serum level of IL-۱۸ and other metrics, including high-sensitivity C-reactive protein (hs-CRP), cholesterol, triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), anti-double stranded deoxyribonucleic acid (anti-dsDNA), complement ۳ (C۳), and C۴. The IMT of the carotid artery was calculated in both groups. We also evaluated the clinical cardiovascular manifestations.RESULTS: The serum IL-۱۸ levels in patients were significantly higher than in the control group (P ˂ ۰.۰۰۵). It had no significant correlation with disease activity (P = ۰.۱۰). The patients with SLE with high IL-۱۸ serum levels (> ۲۸۰ pg/ml) had higher SLEDAI-۲K (P = ۰.۰۲) than the patients with a low level (< ۲۸۰), where ۲۸۰ was the median of the IL-۱۸ levels. The serum IL-۱۸ level had no significant correlation with the carotid artery IMT.CONCLUSION: A high level of IL-۱۸ reflects the disease activity, but it was not significantly correlated with subclinical atherosclerosis, denoted by the carotid artery IMT.