Background: The imbalance between the oxidant and antioxidant defense systems may play a role in the etiopathogenesis of juvenile idiopathic arthritis (JIA).Nitric oxide (NO) is a free radical and malondialdehyde (MDA) is a product of polyunsaturated fatty acid peroxidation and both are possibly implicated in the pathogenesis of chronic synovitis. Objective: We sought to investigate the role of serum NO and MDA as markers for oxidative stress in JIA and their relation to activity and therapeutic modalities used . Methods: This comparative prospective study included 20 children with pediatric JIA enrolled consecutively from the Pediatric Allergy, Immunology and Rheumatology Unit, Children's Hospital, Ain Shams University. They were compared to 20 matched healthy control subjects. They underwent clinical evaluation and measurement of serum NO and MDA by enzymatic immunoassay was performed in both groups .
Results: A significant positive correlation was found between serum NO and MDA concentrations and JIA activity (p=0.0150; p=0.037 respectively). Patients who had arthralgia, arthritis and/or morning stiffness had significantly higher Serum NO and MDA concentrations. According to ROC analysis, serum NO levels above 158.9 μ mol/L and serum MDA levels above 6.75 m mol/L had 100% sensitivity and specificity in the prediction of disease activity (AUC= 0.99-1.0). Patients treated with methotrexate (MTX) had significantly higher MDA concentrations and a significant positive correlation between serum NO and MTX dosage. Conclusion: Serum NO and MDA levels were significantly elevated among patients during disease activity which may suggest a significant role in the etiopathogenesis of JIA. Further studies are needed to validate their usefulness as predictors of JIA outcome