Original Research Article Correlation between Plasma Interleukin-18 Level and Disease Activity in Jordanian Patients with Rheumatoid Arthritis

Background: Interleukin 18 (IL-18) is a newly defined cytokine that has an important role in the Th1 type immune response and it shares similar functional properties with IL-12. Elevation of IL-18 levels in autoimmune diseases such as SLE has been reported in previous studies whereas in Rheumatoid Arthritis (RA) no study has been conducted in plasma IL-18 on the same aspect. Aims & Objectives: To study the IL-18 levels in the plasma of Jordanian patients suffering from Rheumatoid arthritis and to correlate the disease activity and IL-18 level. Materials and Method: The study includes forty-one RA patients in experimental group, and forty-one as a control group, sex and age matched apparently healthy subjects. Plasma IL-18 levels were determined using enzyme-linked immuno sorbent assay (ELISA). Results: IL-18 levels were significantly elevated in the RA patients compared to the controls (p< 0.0001). However, there was no significant correlation with disease activity in RA patients (r =-0.205, p=0.198, r=-0.196, p=0.22.respectively). Conclusion: Elevated IL-18 levels were noticed in patients with RA. IL-18 levels are not correlated with disease activity in RA patients