Gene expression predictors of extension in oligoarticular juvenile idiopathic arthritis (JIA)

Children with oligoarticular JIA (arthritis in 4 or fewer joints) can either continue to have this mild form of arthritis (persistent oligoarticular JIA) or extend to a more sever form involving more than 4 joints (extended oligoarticular JIA) Synovial fluid mononuclear cell RNA was prepared from 21 recently diagnosed pre-treatment patients and grouped according to whether the patient had extended or persisted at one year after diagnosis Each sample was hybridized to Affymetrix HGU133plus2 microarrays. The mean for each probeset was compared between groups in order to find differentially expressed genes whose expression might predict outcome in a prospective study