PREDICTORS OF JOINT DAMAGE IN RHEUMATOID-ARTHRITIS

Rheumatoid arthritis (RA) is the dominant form of destructive chronic arthritis with the potential to cause substantial disability and perma nent functional impairment. The final extent and progression rate with time, however, varies markedly In order to study effects of intervent ion and to support early aggressive and atoxic therapy in selected cas es, predictive disease markers are needed. Recent advances regarding j oint tissue composition and pathophysiology have defined a number of b iological marker candidates which need to be explored for possible pro gnostic information. Some markers are characteristic for RA, such as r heumatoid factors and certain autoantibodies, which although they are more prevalent among patients with aggressive disease are not sensitiv e as predictors in early disease. Genetic susceptibility markers have been claimed to be good predictors of persisting arthritis in early sy novitis clinics, but their role as severity markers in established dis ease is limited. Unspecific markers of inflammation, notably ESR or CR P when persistently elevated, are useful to monitor disease course and newer markers need to document their superiority over these. Another group of markers are attractive because of enriched or exclusive occur rence in joint tissue, and altered metabolism in joint disease. Thus, collagen type III propeptides, hyaluronates, and neopterin originating in the synovium could be useful, and, in particular, hyaluronate leve ls indeed do provide some predictive information. Highly tissue-specif ic cartilage metabolites include aggrecan fragments, collagen II fragm ents, cartilage oligomeric matrix protein (COMP) and the extraarticula r cartilage matrix protein (CMP). When used alone or in combination in early disease some information can be obtained which may in the futur e facilitate prognostication. Bone metabolism can be monitored and the re are different markers for synthesis and resorption. Meanwhile, whil st the new markers are essential research tools, their routine clinica l usefulness remains to be proven.