The diagnosis of rheumatoid arthritis (RA) remains imprecise, particularly early in the course of the disease. Up to now, rheumatoid factor (RF) has been used as a typical marker for RA; however, RF has a low specificity because it also occurs in many inflammatory diseases as well as in healthy people. It has recently been shown that autoantibodies directed toward cyclic citrullinated peptides (anti-CCP) are potentially important serological markers for diagnosis and prognosis in RA.¹

The proteolytic pathways associated with cellular interactions also seem to have an important role in joint cartilage destruction of RA. Matrix metalloproteinase-3 (MMP-3) is secreted by fibroblasts and synovial cells,² and it has been shown to be increased in RA serum, not only in the late stage but also in the early stage of the disease. Therefore, MMP-3 is a useful marker for predicting bone damage in early RA.³

In many early cases of RA, patients will not always fulfil the American …