Review Autoantibody profile in juvenile chronic arthritis

SUMMARY Patients with juvenile chronic arthritis (JCA) may be subdivided into a minority, who carry IgM rheumatoid factor and have erosive polyarthritis resembling adult rheumatoid arthritis, and the majority (9O0/o), who are seronegative by conventional means. Between 30 and 60 % of patients with JCA have positive antinuclear antibodies (ANAs) according to the choice of substrate for indirect immunofluorescence. The importance of ANAs is the frequent develop-ment of associated asymptomatic chronic iridocyclitis, which may impair vision causing worse handicap than the arthritis, which remains predominantly pauciarticular in two thirds of these young children. ANA positive patients rarely possess antibodies to deoxyribonucleic acid (DNA) or extractable nuclear antigens (ENA), and current studies suggest that several different nuclear antigens, including histones, may be involved. Key words: antinuclear antibodies, rheumatoid able nuclear antigens. Juvenile chronic arthritis (JCA) encompasses a heterogeneous group of disorders whose clinical subdivisions have been supported by immunogen-etic studies. ' 2 Among numerous immunological abnormalities detected in JCA only antinuclear antibodies (ANAs) and IgM rheumatoid factor (RF) are currently thought to be useful in patient clas-sification and management.3 About 10 % of children with JCA have a seroposi-tive arthritis resembling adult rheumatoid arthritis,4 but most never develop IgM RF measured by conventional Rose-Waaler techniques.5 Of those with seronegative disease, 2(-30 % have a systemic onset, and the remainder have either a pauciarticu-lar or polyarticular arthritis.6 Children with seronegative polyarthritis may be ANA positive, but ANAs are most often found in children with late onset seropositive polyarthritis or in early onset pauciarticular arthritis, particularly when complicated by chronic iridocylitis.7 The specificity of the ANAs is unknown, and serum samples from these patients do not react with any o