Elevated serum level of IL-33 and sST2 in patients with ankylosing spondylitis: associated with disease activity and vascular endothelial growth factor.

OBJECTIVE

Interleukin (IL)-33 is a cytokine belonging to the IL-1 family and was recently identified as a ligand for ST2, which belongs to the IL-1 receptor (IL-1R) family. In this study, we aimed to investigate the possible pathophysiological role of IL-33/sST2 in ankylosing spondylitis (AS).

METHODS

The levels of IL-33/sST2 and vascular endothelial growth factor in serum samples of 140 patients with AS and 90 controls were measured by enzyme-linked immunosorbent assay. Erythrocyte sedimentation rate, C-reactive protein level, and human leukocyte antigen B27 were measured by standard laboratory techniques. Disease activity in AS was measured by the Bath Ankylosing Spondylitis Disease Activity Index. Hip involvement, peripheral arthritis, and eye involvement were also recorded.

RESULTS

The serum levels of IL-33/sST2 were remarkably higher in the patients with AS than the healthy groups and significantly correlated with vascular endothelial growth factor and the Bath Ankylosing Spondylitis Disease Activity Index. The sST2 levels correlated with erythrocyte sedimentation rate, C-reactive protein, platelet, and human leukocyte antigen B27. Elevated levels of IL-33/sST2 were detected in the patients with peripheral arthritis, and sST2 were detected to be increased in the patients with hip involvement. By contrast, levels of IL-33 but not sST2 increased in the patients with eye involvement.

CONCLUSION

IL-33/sST2 may regulate the immunological or inflammatory process of AS.