Biomarkers of rheumatoid arthritis: recent progress

Biomarkers are emerging as vital tools for early diagnosis, prognostication and disease management in chronic diseases, including rheumatoid arthritis (RA).

This review discusses diagnostic, prognostic and theranostic biomarker candidates for RA that are being studied at present.

The reader will gain a better understanding of the different classes of markers being proposed as potential biomarkers for RA, and how they compare with each other.

At present, several molecules are showing varying degrees of promise as potential biomarkers in RA. These include serum rheumatoid factors and anti-cyclic citrullinated protein antibodies, a couple of acute phase proteins and pro-inflammatory cytokines expressed in the serum and/or diseased joints, notably IL-1, IL-6, TNF-α, MCP-1 and MIP-α, as well as molecules released by damaged synovial tissue, cartilage and bone. Continuing proteomic and metabolomic efforts are rapidly expanding this repertoire of potential biomarker candidates. Large-scale longitudinal trials are clearly needed where several biomarker candidates can be assessed in parallel, relative to current yardsticks. The ultimate goal is to distill out a subset of informative biomarkers, presumably representing distinct pathogenic pathways, which will enable the rheumatologist to prognosticate, predict and actively manage the disease course in RA.