Soluble adhesion molecules ICAM-1 and E-selectin in juvenile arthritis: clinical and laboratory correlations

To determine serum and synovial fluid (SF) concentrations of soluble intercellular adhesion molecule-1 (ICAM-1) and E-selectin (E-sel) in patients with active juvenile idiopathic arthritis (JIA) and in paediatric controls and correlate them with clinical and laboratory variables.

Total of'30 JIA patients were evaluated: 15 with polyarticular disease course (JIA-poly) and 15 with oligoarthritis (JIA-oligo). Paediatric age-matched control groups consisted of 11 Henoch-Schönlein purpura (HSP) and 10 febrile patients (FC) and 28 healthy children (HC). Current medication, the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and full blood count (FBC) were recorded. Soluble ICAM-1 and E-sel in serum and SF were measured by a sandwich ELISA kit.

In the JIA-poly group the concentration of ICAM-1 was significantly higher than in healthy (p < 0.01), but notfebrile controls. Both ICAM-1 and E-selectin correlated with the active joint count (p < 0.01). In 13 JIA patients no correlanon was found between SF ICAM-1 and E-sel levels and the SF leucocyte counts. No significant differences were seen in the disease control and JIA-oligo groups compared to HC. A significant negative correlation with age was observed for the group as a whole (ICAM-1: p < 0.05, E-sel: p < 0.01); E-sel correlated with the leucocyte and thrombocyte counts (p < 0.01), and both molecules with CRP (p < 0.05) and with each other (p < 0.01).

A high concentration of soluble ICAM-1 in JIA patients with polyarthritis is reported here for the first time. None of the patients showed signs of injection or vasculitis, where generalised endothelial activation could be its main source. Our finding of correlations between both ICAM-1 and E-sel levels and joint counts supports the hypothesis of their synovial origin. ICAM- I and E-sel could serve as a marker of aggressive disease, but their predictive value needs to be further studied.