TYPE-I COLLAGEN DEGRADATION PRODUCT IN SERUM OF PATIENTS WITH EARLY RHEUMATOID-ARTHRITIS - RELATIONSHIP TO DISEASE-ACTIVITY AND RADIOLOGICAL PROGRESSION IN A 3-YEAR FOLLOW-UP

The new assay of cross-linked carboxyterminal telopeptide of type I co llagen (ICTP), a serum marker for bone collagen degradation, was evalu ated in serial measurements of 66 patients with early RA during a 3-yr prospective study. Initially 51% of RA patients had elevated levels o f serum ICTP compared to healthy controls. During the subsequent month s after starting anti-rheumatic treatment, the mean ICTP levels decrea sed in parallel with the clinical and laboratory variables measuring d isease activity. Despite marked clinical improvement with anti-rheumat ic treatment, a steady increase in radiological progression of joints was observed. Throughout the follow-up serum ICTP levels correlated wi th inflammatory parameters and from the first year on with the radiolo gical changes assessed annually. However, initial serum ICTP levels co rrelated better than the other variables of disease activity with the subsequent erosive progression of joints indicating that measurement o f serum ICTP may serve as one of the prognostic markers for joint dama ge in early RA.