Serum-soluble ST2 and systemic sclerosis arthropathy

Interleukin (IL)33 and its receptor ST2 have been involved in the pathogenesis of several conditions, including arthritis. The aim of the study was to evaluate the association between IL33 or soluble ST2 (sST2) serum levels and systemic sclerosis (SSc) articular involvement. IL33 and sST2 serum levels were measured in 64 SSc patients and 24 HC matched for sex and age. Articular involvement assessed by using Disease Activity Score 28 based on erythrocyte sedimentation rate (DAS28-ESR), presence of tendon friction rubs (TFRs) and finger-to-palm (FTP) distance. sST2 serum levels were significantly higher in SSc patients with DAS28-ESR > 3.2 than in SSc patients with DAS28-ESR <= 3.2 [9726.1 (IQR 7746.5 - 14,953.5) pg/mL vs 7611.7 (IQR 5162.6 -11,036.7) pg/mL; p <0.05]. sST2 serum levels were significantly higher in SSc patients with TFRs compared to SSc patients without TFRs [9726.1 (IQR 7746.5 - 14,953.5) pg/mL vs 7426.4 (IQR 5145.9 - 10,593.5) pg/mL; p< 0.01] and in SSc patients with FTP >= 1 cm compared to SSc patients with FTP < 1 cm [9683.7 (IQR 8067.2 - 16,387.6) pg/mL vs 7679.1 (IQR 5246.1 - 11,472.2) pg/mL; p< 0.05]. No significant association was observed between IL33 and DAS28-ESR, TFRs and FTP. A slightly positive linear correlation was found between sST2 and Disease Activity Index (r=0.294, p <0.05) and Disease Severity Scale (r=0.265, p <0.05). sST2 serum levels were positively correlated with DAS28-ESR (r=0.371, p <0.01). Elevated sST2 serum levels were associated with higher articular disease activity, TFRs and hand dysfunction, suggesting that sST2 might have a role in the pathogenesis of SSc articular involvement.