Serum N terminal procollagen III fragment: a predictive marker of joint destruction in rheumatoid arthritis?

The level of the N terminal fragment of procollagen III (P3NP) levels of 100 consecutive patients affected by rheumatoid arthritis (RA) were evaluated in comparison with disease activity markers (erythrocytes sedimentation rate, C reactive protein), immunological status (rheumatoid factors, immune complexes) and joint destruction (assessed according to the Steinbrocker index). P3NP levels showed no significant relationship either to disease activity or to immunological status; however, a strong association was fond between X-ray grade and P3NP values. A two-year retrospective study of 32 patients belonging to the original 100 patient population allowed us to assign a predictive value for joint destruction to the P3NP level in the early stage of the disease.