Assessment of bone morphogenic protein 2 and interleukin-17A in patients with axial spondyloarthritis and their potential role in the new bone formation: a cross-sectional study.

OBJECTIVES

Several molecules are involved in the pathogenesis of new bone formation in axial spondyloarthritis (axSpA). The aim of this study was to evaluate the serum levels of BMP-2 and IL-17A in patients with axSpA and their possible correlations with radiographic damage, disease activity, and function.

METHODS

AxSpA patients fulfilled the ASAS criteria and with at least New York grade 2 bilateral sacroiliitis and healthy matched controls were enrolled for this study. BASDAI, ASDAS-CRP, BASMI, BASFI and CRP were evaluated as measures of disease activity and function. Spinal damage was assessed using the mSASSS on radiographs performed within 3 months from baseline. Serum concentrations of BMP-2 and IL-17A were assessed using ELISA kit.

RESULTS

Sixty patients and 30 healthy subjects satisfying the inclusion criteria were enrolled. In our axSpA group, serum BMP-2 levels [median (25th-75th percentile) of 589.2 (430.24-1017.1) pg/ml] did not statistically differ from controls [518.34 (450.2-1028.2) pg/ml]. However, significant correlations were found between serum BMP-2 levels and radiographic damage assessed by mSASSS, and BMP-2 levels were found to be higher in patients with grade 4 sacroiliitis when compared to patients with lower grade of sacroiliitis. Of note, serum BMP-2 levels significantly inversely correlate with IL-17A levels and CRP, and were found to be lower in patients with higher disease activity.

CONCLUSIONS

The results of our study may confirm a possible role of BMP-2 in the pathogenesis of new bone formation in axSpA patients. Furthermore, a link between inflammation and BMP-2 was found.