Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) refers to a group of immune-mediated disorders first appearing before 16 years of age, that share in common joint inflammation as their main clinical manifestation. The 2001 International League of Associations for Rheumatology (ILAR) classification defines seven sub-types of JIA. However, a number of shortcomings have been identified in the ILAR classification, including the tenuous nature of the biologic distinctions between certain subtypes, and lack of integration with classifications widely used for adults with rheumatic disease. Accordingly, the Pediatric Rheumatology International Trials Organization (PRINTO) has published a revised, draft classification, which partially addresses some of these issues. It is expected that classification of pediatric arthritis will evolve further as understanding of the genetic and immune mechanisms underlying the different forms of chronic arthritis in childhood advances.