Autoantibodies and other serological markers in rheumatoid arthritis: predictors of disease activity?

The description of potential serological markers of rheumatoid arthritis (RA) activity can be quite useful in optimizing RA treatment, since the laboratory markers currently used, namely erythrocyte sedimentation rate and C-reactive protein, are not specific for RA and are influenced by several other variables. The markers proposed for assessing RA activity include rheumatoid factor, anti-citrullinated protein/peptide antibodies, immunoglobulin M (IgM) anti-IgG advanced glycation end products, markers of bone/cartilage metabolism, mannose-binding lectin, E-selectin, interleukin-6, and leptin. Various studies have investigated the correlation between some of these markers and other variables that might indicate disease activity, e.g., inflammatory activity tests and disease activity scores. However, there is as yet insufficient evidence that any of these markers, in isolation or in combination, are useful in the assessment of RA activity.