Comparison of Serum Levels of 14-3-3 ETA Proteins between Rheumatoid Arthritis, Osteoarthritis and Normal Controls

Abstract

14-3-3 ETA protein, a joint-derived biomarker that up-regulates inflammatory cytokines which enhances local and systemic inflammation and may lead to destructive changes in joints, is thought to be a good diagnostic marker for early RA. To assess the usefulness of serum levels of 14-3-3 ETA in the diagnosis of RA. This is a case-control study which involved 3 groups: group 1 included 30 RA patients, group 2 included 30 primary osteoarthritis patients and group 3 included 30 healthy controls. All study subjects were assessed using laboratory investigations as CBC, ESR, CRP, RF, ACPA as well as serum levels of 14-3-3 ETA protein which were measured through ELISA technique. Mean ± SD levels of 14-3-3 ETA were significantly higher among RA compared to OA and control groups (0.7(0.5), 0.2 (0.1) and 0.3(0.1) ng/ml, respectively) with a sensitivity of 79.3%, specificity of 81.7%, positive predicted value of 86% and negative predicted value of 81%. 14-3-3 ETA also had high diagnostic OR (1478.04). A statistically significant correlation (r= 0.259) was found between serum levels of 14-3-3 ETA and ESR. In conclusion, 14-3-3 ETA is a novel marker for RA that should be used in conjunction with RF and ACPA for diagnosis of the disease.