Sugar-Coded Signals: Glycan-Based Biomarkers in Rheumatoid Arthritis.

This review paper summarizes the pathophysiology of rheumatoid arthritis (RA), its incidence and etiology, and conventional RA protein-based biomarkers. A brief overview of novel protein-based biomarkers and biomarkers with potential to be used in the diagnostics of seronegative RA is also provided. The core of the review resides in the comprehensive characterization of the glycosylation of immunoglobulins and their utility as novel biomarkers for the diagnostics of RA and seropositive RA. Two main approaches to the analysis of glycans present on immunoglobulins and other proteins are provided, including instrument-based and lectin-based approaches showing their clinical performance as RA biomarkers.