Semaphorin 3A in Ankylosing Spondylitis.

BACKGROUND/PURPOSE: To determine serum semaphorin 3A (Sema 3A) levels in ankylosing spondylitis (AS).

METHODS

Serum Sema 3A was measured in 46 AS patients and 30 healthy controls (HCs). For the patients, we recorded demographic data, disease activity, functional index & global assessment, detected human leukocyte antigen-B27 (HLA-B27), and measured erythrocyte sedimentation rate (ESR) & C-reactive protein (CRP).

RESULTS

Sema 3A was higher in AS patients than in HCs (3.98 ± 2.57 vs. 1.34 ± 0.48 ng/ml, p = 0.013). Area under the curve (AUC) of standard receiver operating characteristic (ROC) has suggested that Sema 3A > 2 ng/ml is better to predict the higher Bath Ankylosing Spondylitis Disease Activity Index (BASDAI, > 4) than ESR or CRP. There were good correlations between higher Sema 3A and uveitis, Schöber's test, as well as interstitial lung disease. AS patients undergoing anti-tumor necrosis factor therapies for 3 months exhibited a positive correlation of change in Sema 3A (ΔSema 3A) with disease activity fluctuation [ΔBASDAI, ΔBath Ankylosing Spondylitis Functional Index (BASFI) and ΔBath Ankylosing Spondylitis - Global score (BAS-G)].

CONCLUSION

Serum Sema 3A level was increased in AS patients and was inversely correlated to Schöber's test. Serum Sema 3A is better as a bio-marker than ESR or CRP to correlate with high disease activity in AS patients, and it is also a good indicator for monitoring disease activity and functional status during anti-TNF treatment. Also, Sema 3A may be taken as a predictor for extra-articular presentations in AS, but this needs further study to elucidate.