Background/Purpose:

Monocytes of patients with Ankylosing Spondylitis (AS) over-express Toll-like receptor (TLR) 4 on their monocytes. Tenascin-C (TNC) is an extracellular-matrix-glycoprotein and acts as an endogenous TLR4 ligand. Thus we studied the serum and synovial fluid levels of TNC in adults with AS.

Methods:

TNC was measured in serum of 36 AS patients (ASAS 2009 criteria) and 10 healthy controls by ELISA. 22 patients were followed-up after 3 months of standard of care treatment. Five paired serum-synovial fluid samples were also analyzed. Disease activity was assessed by BASDAI, ASDAS, tender and swollen joint count; enthesitis score, ESR and CRP. All values are in median (IQR).

Results:

Median age was 30 (20-35) years and disease duration 5.5(1.3-10) years. 31 were male and 5 female. 25 cases had peripheral arthritis (69.5%). Median BASDAI was 5.3(3.3-6.7). HLA B27 was positive in 34 (94.5%) cases.

Median serum Tenascin C levels were higher in AS [554.6ng/ml] as compared to healthy controls [32.88 ng/ml, p<0.00001]. Serum TNC levels correlated with ASDAS ESR [r=0.367, p=0.028] and ESR [r=0.39, p=0.035]; but not with other disease activity measures. In patients with disease duration less than 5 years (early disease) serum levels had better correlation with ESR [r=0.59, p=0.009] and CRP [r=0.479, p=0.044]. On ROC analysis for active (PhGA≥6) vs. inactive (PhGA≤4) disease, TNC (AUC=0.60) performed as well as CRP (AUC=0.65) and ESR (AUC=0.73). The synovial fluid levels [11.61(5.99-176.9) ng/ml] were lower than in the serum [627.4 (488.5-779.1) ng/ml, p=0.008].

TNC levels fell with treatment [630.8 ng/ml to 376.4 ng/ml p=0.0006] in treatment responders (n=11) but not in non- responders (n=11) [562.3 to 445.6,p=0.33].

Conclusion:

Serum TNC levels are significantly raised in AS and can serve as marker of inflammation in early disease. Treatment reduces the TNC levels, probably due to control of disease activity.

« Back to 2017 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/tenascin-c-a-tlr-4-endogenous-ligand-levels-are-increased-in-ankylosing-spondylitis/