Abstract
This article provides an up-to-date survey of conventional and investigational disease activity markers for rheumatoid arthritis. Measurements of clinically-assessed synovitis, radiographic damage, rheumatoid factor, acute phase reactants, and synovial white blood cell counts exemplify the traditional repertoire of markers used to evaluate disease progression. However, advances in the pathophysiology of rheumatoid arthritis and joint tissue composition have fostered the development of more sophisticated laboratory assays and radiologic technologies. Measurements of bone and cartilage turnover as well as the production of abnormal antibodies, matrix-degrading enzymes, and mediators of inflammation are emerging as tools to detect rheumatoid synovitis and joint degradation. In the future, well-defined patient profiles (even at the molecular level) may be exploited to detect the severity of rheumatoid arthritis and to gauge the efficacy of therapeutic intervention.