Salivary gland involvement and oxidative stress in juvenile idiopathic arthritis: novel observation in oligoarticular-type patients.

Objective: The salivary glands may become affected in various collagen diseases, but their involvement in juvenile idiopathic arthritis (JIA) has received little attention. We studied the salivary composition and the antioxidant profile in patients with JIA, as well as their serum antioxidant status.
Methods: Twenty-two children with JIA according to the American College of Rheumatology criteria (10 oligoarticular, 7 polyarticular, and 5 systemic-type) and 15 healthy controls were studied. Serum and saliva samples were obtained simultaneously and analyzed.
Results: Significantly raised levels of antioxidant enzyme activity were observed in the patients with JIA, in both saliva and serum. The salivary peroxidase activity was significantly higher in the total group of patients with JIA by 8.5% (p < 0.01) as compared to controls (0.76 vs 0.70 mU/ml). Salivary superoxide dismutase was found to be significantly increased mainly in the patients with systemic JIA (by 74%; p < 0.02). Significantly higher levels of peroxidase activity were observed in serum of patients with JIA, particularly of the polyarticular group, by 17% (p < 0.05). Major changes in saliva composition were observed in patients with oligoarticular disease compared to controls: the patients had a lower salivary flow by 33%, less acidic saliva, and significantly lower salivary levels of magnesium by 44% (p < 0.01), total protein by 44% (p < 0.02), amylase by 34% (p < 0.02), and lactate dehydrogenase by 62% (p < 0.02).
Conclusion: Children with JIA exhibited a major increase in antioxidant enzyme activity, both in serum and in saliva. Patients with oligoarticular JIA displayed indications of significant and specific damage to the salivary glands, a novel observation.