Sialic acids are a diverse family of sugar units attached to the outermost ends of sugar chains, which were demonstrated to be related to many diseases. We hypothesized sialic acids could be used as biomarkers for diagnosis of rheumatoid arthritis (RA).
The serum level of the main sialic acids, N-acetyl-D-neuraminic acid (Neu5Ac) in 163 RA patients and 50 healthy individuals were detected by pre-column derivatization-high performance liquid chromatography method. And three biomarkers to diagnose RA in clinic, C-reactive protein (CRP), rheumatoid factor (RF), and cyclic citrullinated peptides (CCP) in serum of these subjects were analyzed using enzyme-linked immunosorbent assay (ELISA). The data was analyzed using the receiver operating characteristic (ROC) curve and the Youden index.
We found the concentration of Neu5Ac in RA group was significantly higher than healthy group. There was a positive correlation between the concentration of Neu5Ac and the RA disease activity score (DAS). The sensitivity and specificity of Neu5Ac were significantly greater than CRP, RF, CCP.
Higher serum levels of Neu5Ac were significantly associated with the presence as well as severity of RA. Neu5Ac may be a potential biomarker for prediction and severity of RA in clinical practice.