JKAP serves as a potential biomarker for the evaluation of inflammatory condition, disease activity, and treatment response to TNF inhibitor in ankylosing spondylitis patients.

OBJECTIVE: This study aimed to evaluate the value of JKAP as a biomarker in estimating treatment response to TNF inhibitor in AS patients.
METHODS: Totally, 63 AS patents who planned to receive adalimumab (TNF inhibitor) treatment were enrolled. Baseline JKAP level was determined in serum samples. All patients received 40 mg adalimumab every two weeks for 12 weeks. At W2, W4, W8, and W12, ASAS40 response rates were evaluated.
RESULTS: JKAP was negatively correlated with CRP (P = 0.032), BASDAI score (P = 0.021), BASFI score (P = 0.045), ASDASCRP score (P = 0.038), TNF-α (P = 0.031), IL-6 (P = 0.025) and IL-17A (P = 0.022). The ASAS40 response rates were 17.5%, 31.7%, 44.4% and 55.5% at W2, W4, W8 and W12, respectively. Baseline JKAP level was lower in patients with ASAS40 response than those without ASAS40 response (25.8 (13.2-42.7) pg/mL vs. 47.3 (26.7-71.2) pg/mL, P = 0.003). Multivariate logistic regression disclosed that JKAP level (P = 0.049) and CRP level (P = 0.014) independently correlated with ASAS40 response; further analyses disclosed that they exhibited acceptable to good ability in distinguishing patients with ASAS40 response from those without ASAS40 response.
CONCLUSION: JKAP serves as a potential biomarker for evaluation of inflammatory condition, disease activity, especially for assessing treatment response to TNF inhibitor in AS patients. © Japan College of Rheumatology 2021. Published by Oxford University Press.