The development of the International League of Associations for Rheumatology (ILAR) classification of juvenile idiopathic arthritis (JIA) in the 1990s represented a significant change in thinking about childhood-onset arthritis. It combined the similar but disparate concepts of juvenile rheumatoid arthritis and juvenile chronic arthritis to create mutually exclusive categories of JIA1. Always intended as a stepping stone rather than as a final categorization schema, the weaknesses of the ILAR classification are by now well documented, including lack of validation, overly restrictive exclusion criteria, and inclusion criteria often not assessed clinically.
Clearly, creating disease nomenclature is difficult. An ideal classification system brings together disorders that share key elements of pathophysiology, clinical features, prognosis, and response to treatment. In this issue of The Journal, Professor Alberto Martini and colleagues continue the quest to improve the categorization of childhood-onset arthritis2. Under the sponsorship of the Pediatric Rheumatology International Trials Organization (PRINTO), an international group of 13 senior pediatric rheumatologists applied established consensus methodologies to propose new JIA classification criteria. The results are predictably controversial.
Perhaps most puzzling is the proposal that JIA, despite its name, is no longer a collection of arthritides but rather simply “a group of inflammatory disorders that begins before the 18th birthday and persists for at least 6 weeks.” There is little here to distinguish JIA from all other chronic inflammatory diseases of childhood. The motivation is to keep systemic arthritis within JIA while dropping the requirement for arthritis (more on this later). They preserve “JIA” because the US Food and Drug Administration and the European Medicines Agency use the term in product labeling, a plausible rationale, although neither agency strictly adheres to ILAR nomenclature. Reasonable alternatives would have been to allow systemic JIA to have an arthritis exception or to remove it from JIA …
Address correspondence to Dr. T. Beukelman, The University of Alabama at Birmingham, Division of Pediatric Rheumatology, 1600 7th Ave. South, CPP 210, Birmingham, Alabama 35233-1711, USA. E-mail: tbeukelman{at}peds.uab.edu