Early studies showed few immunologic abnormalities in
juvenile rheumatoid arthritis (JRA) patients. There were no specific
laboratory markers useful for diagnosis and assessment of the course of disease in JRA. Previous work showed an association of
antinuclear antibodies (ANA) with early-onset pauciarticular disease and
iridocyclitis. Similarly, the presence of 19S
immunoglobulin (Ig) M rheumatoid factors (RF) was associated with late-onset polyarticular disease in girls. More recent studies have detected many unique
autoantibodies. Newer assays show 19S
IgM RF in up to 35% of JRA patients, although still mainly in girls with late-onset polyarticular disease. Hidden 19S
IgM RF can be shown in up to 75% of JRA patients using different procedures, primarily in those with active polyarticular-or pauciarticular-onset disease.
Immune complexes have been detected in JRA patients by means of different techniques; their presence usually correlates with active disease. Studies on a specific ANA in JRA have shown no common
extractable nuclear antigen, but antihistone
antibodies have been found in up to 75% of cases, again mainly in those with pauciarticular onset and
iritis. Finally, a variety of unusual immunologic
proteins have also been detected, including anti-ocular, anti-cellular, anti-
cardiolipin, anti-perinuclear factor, and anti-
collagen antibodies. This review evaluates the significance of these
antibodies that can now be found in JRA.