The diagnostic value of 14-3-3η protein levels in patients with rheumatoid arthritis

14-3-3 eta may represent a useful diagnostic biomarker for rheumatoid arthritis (RA). We assessed the prevalence and serum levels of 14-3-3 eta in patients with RA and in patients with other rheumatic diseases. Serum levels of 14-3-3 eta were measured in 96 patients with RA, in 101 patients with other rheumatic diseases, and in 66 healthy subjects. All of the sera samples were evaluated by JOINT stat 14-3-3 eta ELISA test kits (Augurex Life Sciences Corp.). Median (IQR) 14-3-3 eta levels were significantly higher in the early RA group [0.25 ng/ml (0.075-3.11)] and in patients with established RA [0.15 ng/ml (0.08-1.26)] than in healthy subjects [0 ng/ml (0-0)] and disease controls: SLE [0.01 ng/ml (0-0.055)], AS [0.05 ng/ml (0-0.255)], and PsA [0.01 ng/ml (0-0.065)]. The prevalence of 14-3-3 eta positivity in patients with early RA was 58%, significantly higher than that in disease controls and healthy subjects (p < 0.001). In patients with established RA, this prevalence was 43%, and it was significantly higher than that in patients with other rheumatic diseases and healthy subjects (p < 0.05), excluding the AS group (p = 0.054). In the early RA cohort, the positivity for 14-3-3 eta, RF, and anti-CCP was 58%, 67%, and 71%, respectively. Eighty-two percent of the patients in this cohort were positive for at least one of these biomarkers. The concentration of 14-3-3 eta protein may be used to distinguish between patients with early RA and patients with other rheumatic diseases. (C) 2019 Elsevier Ltd. All rights reserved.