The continuous measurement of anti-CCP-antibodies does not help to evaluate the disease activity in anti-CCP-antibody-positive patients with rheumatoid arthritis

Abstract

Anti-cyclic citrullinated peptide antibody (CCP-AB) are used for diagnosis of rheumatoid arthritis (RA). It is still unknown if the extent of CCP-AB levels is useful to assess the disease activity or the individual follow-up as an individual activity parameter. We investigated 40 patients with a known RA who were positive for CCP-AB. Correlation between disease activity (DAS 28) and the amount of levels of CCP-AB in all patients over time as well as the individual follow-up were analysed. A weak correlation between CCP-AB and DAS 28 [r = 0.19; p = 0.001] was found. The individual correlation between CCP-AB titre and DAS 28 ranged between r = -1 and r = 1, so a strong positive and also a strong negative correlation was seen in single patients. In patients with erosive RA the correlation was significantly more positive than in patients with non-erosive RA. Because the correlation between CCP-AB levels and parameters of disease activity measured by DAS 28 is very low, we conclude for monitoring the disease activity to use simply and established parameters like morning stiffness, HAQ or ESR. The individual follow-up of the levels of CCP-AB is by the moment not useful for monitoring the disease activity.