Scatterplots showing plasma levels of S100A8/A9 complexes in children with juvenile rheumatoid arthritis (JRA) and healthy controls (n = 10). (a) Comparison of all children with JRA (n = 24) at the time the initial sample was obtained for analysis. S100 proteins were markedly elevated in children with JRA (662 ± 40 ng/ml) compared with controls (40 ± 9 ng/ml; p > 0.001). Although S100A8/A9 levels were higher in children with active disease than with inactive disease (198 ± 60 ng/ml; p = 0.007) (b), S100 protein levels were significantly higher (p = 0.047) in children with inactive JRA compared with controls (c). Ctr, control.