The Correlation Between Plasma Interleukin-18 Level And Disease Activity In Jordanian Patients With Different Connective Tissue Diseases

Abstract 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 Systemic Lupus Erythematosus SLE has been reported in previous studies. Aims 26 Objectives To study the IL-18 levels in the plasma of Jordanian patients suffering from Rheumatoid Arthritis RA Systemic Lupus Erythematosus SLE and Behcets disease and to correlate the disease activity and IL-18 level for the three diseases. Materials and method The study includes one hundred and twenty three patients forty-one patients for each disease 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 three study group compared to the controls p 0.0001. The level of IL-18 was significantly correlated with the disease activity in SLE patients r 0.602 p 0.000. However there was no significant correlation with disease activity in RA patients r -0.205 p0.198 r -0.196 p0.22.respectively. In case of Behcets disease there was no significant difference between active and inactive disease. Conclusion Elevated IL-18 levels were noticed in patients with SLE RA and Behcetss disease. IL-18 levels are significantly correlated with disease activity in SLE patients only. This finding may be of used for monitoring the disease activity in SLE patients.