ANTI-IgG ANTIBODIES IN JUVENILE RHEUMATOID ARTHRITIS

ABSTRACT. Egeskjold, E.-M., Permin, H., Hørbov, S. and Graudal, H. (Rheumatism Research Unit of Aarhus University, Aarhus, Denmark). Anti-IgG antibodies in juvenile rheumatoid arthritis. Acta Paediatr Scand, 70:711,.–Sixty-two patients, 48 children and 14 adults, with juvenile rheumatoid arthritis (JRA) and 62 age and sex matched controls were studied for anti-IgG antibodies of the classes IgG, IgM and IgA by an indirect immunofluorescence method. 88 % of 48 children =≤16 years and in 64 % of 14 patients >16 years with JRA against 2 % of the controls. IgM anti-IgG occurred inIgG anti-IgG occurred in 4 % of the children, in 24 % of the adults and in 2 % of the controls. IgA anti-IgG occurred in 2 % of the patients and in none of the controls. The prevalence of IgG anti-IgG was the same in pauciarticular, polyarticular and systemic cases, whereas the titres were higher in polyarticular than in pauciarticular cases, and higher in children with a disease duration of more than 5 years. Higher titres were related to higher ESR and lower hemoglobin values. The relationship of higher titres to clinically active disease was not statistically significant. No relationship was found to age, sex, age at onset, or to the dureation of disease. The titres were not related to the concentrations of serum IgG or to the titres of antinuclear antibodies. IgG anti-IgG are common to all the clinical types of JRA, whereas antinuclear antibodies separate the systemic type from pauci- and polyarthritis. Their possible pathogenic significance must therefore be different.