Objective: This study aimed to investigate the correlation of Jun N-terminal kinase pathway associated phosphatase (JKAP) with disease risk and inflammation, also to explore the association of its longitudinal change with etanercept (ETN) treatment efficiency in rheumatoid arthritis (RA) patients.
Patients and methods: A total of 107 active RA patients about to receive ETN treatment and 60 healthy controls (HCs) were enrolled in this study. Serum JKAP level was measured by enzyme-linked immunosorbent assay in RA patients (at week 0 (W0), W6, W12, and W24) and HCs (at recruitment). RA patients were categorized into W24 response patients and W24 non-response patients, or W24 remission patients and W24 non-remission patients, respectively, according to clinical response status or remission status at W24.
Results: JKAP level was reduced in RA patients compared with HCs. In RA patients, decreased baseline JKAP was correlated with elevated C-reaction protein level and anti-citrullinated protein antibodies positive status. Moreover, JKAP level was increased during ETN treatment. Subgroup analyses revealed that JKAP level during ETN therapy was increased in W24 response patients, while no difference was discovered in JKAP level among different time points in W24 non-response patients. Meanwhile, JKAP level during ETN treatment was elevated in both W24 remission patients and W24 non-remission patients, however, its increment was more evident in W24 remission patients.
Conclusions: JKAP correlates with reduced disease risk and inflammation, and its increment during ETN treatment associates with commendable treatment efficiency in RA patients.