Connective tissue markers of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a common systemic autoimmune disorder of unknown aetiology. The most common outcome of RA is a progressive development of joint destruction and deformity. Early introduction of disease-modifying antirheumatic drugs seems important for prevention of the long term injuries of articular cartilage and bone. Early diagnosis and selection of patients with rapidly progressive disease therefore is of clinical significance. Routine laboratory tests are valuable in monitoring for renal, hepatic and haematological side effects of medical treatment. Determination of rheumatoid factor contributes to the classification of arthritis as RA, and acute phase reactants are useful for quantifying and comparing the level of inflammatory activity in the course of a given patient. There is, however, a lack of sensitive and specific biochemical markers for RA, and frontline biochemical research is devoted to characterizing molecules which are of diagnostic and prognostic value, as well as molecules which are indicators of the degree of joint cartilage and bone destruction. The present survey summarizes current knowledge concerning possible tissue-specific marker molecules of RA.