Cartilage proteoglycan aggrecan : potential as serum marker of cartilage destruction in juvenile rheumatoid arthritis

الملخص EN

Aim of Work : To investigate whether aggrecan is to be considered a useful marker and a predictor of joint cartilage destruction in juvenile rheumatoid arthritis patients (JRA).

Material & Methods : Aggrecan was quantified with ELISA in sera from 31 children suffering of JRA and synovial fluid (SF) of 10 of them.

Patients were evaluated at baseline and 3 months later.

a) Clinically with the overall articular severity score.

b)Laboratory tests including ESR, CRP, total leucocytic and platelet counts, hemoglobin and rheumatoid factor.

c) Radiologically with modified Larsen, malalignment and vanRossum’s scores.

Radiographs were also repeated after one year.

A group of 15 normal healthy children and another of 10 children with arthritis due to other collagen vascular diseases were studied for comparison.

Results : Baseline serum aggrecan was significantly higher in JRA patients as compared to controls and to patients with other collagen vascular diseases with 93 % sensitivity and 100 % specificity at a cut off level of 18.6 ng / ml (control mean + 3 SD).

On reevaluation, a significant drop of serum aggrecan from baseline values was noticed (p < 0.01) that coincided with a significant drop in clinical and laboratory indices of active inflammation although their levels correlated poorly.

Serum aggrecan levels were insignificantly different from those of SF and both correlated significantly with SF protein concentration.

Lower levels of serum aggrecan were observed in patients with radiographic evidence of joint destruction and in those with evidence of deterioration one year later.

Conclusion : Serum aggrecan can help to assess the extent of cartilage destruction and is useful as a prognostic tool to predict joint damage in patients with JRA.