Leukocyte protein calprotectin and outcome in rheumatoid arthritis

Abstract

Objective: To determine if calprotectin is predictive for outcome in patients with rheumatoid arthritis (RA). Methods: Fifty six RA in-patients with variable disease duration were prospectively followed for five years. Clinical and laboratory data were collected to assess disease activity. Health Assessment Questionnaire (HAQ) and radiographic scores (of hands and wrists) as described by Larsen were used as outcome measures. Plasma calprotectin levels were determined with ELISA technique. Results: Significant correlations (r) were found cross-sectionally at follow-up between calprotectin concentration and other known parameters of disease activity and severity: CRP (r= 0.67), investigator's global assessment of disease activity (r= 0.57), Waaler titre (r= 0.50), HAQ score (r= 0.48) and number of swollen joints (r= 0.48). Calprotectin at baseline was not identified as an independent predictor for HAQ or radiographic progression in the multivariate analysis. Conclusion: The results confirm calprotectin as a good measure of disease activity and joint inflammation in RA. However, the level of calprotectin at baseline was not predictive for radiographic damage or functional impairment five years later.