Serum COMP-C3b increases in patients with ankylosing spondylitis (AS) and PsA on tumor necrosis factor (TNF)-α inhibition. Serum COMP-C3b (a), C-reactive protein (CRP) (b), and COMP (c) were measured in patients with PsA receiving TNF-α inhibition at baseline, after 6 weeks of treatment, and after 3 months of treatment. COMP-C3b (d), CRP (e), and COMP (f) were also measured in AS patients receiving TNF-α inhibition at the same times. Statistical significance of changes in these parameters was measured with a Wilcoxon matched-pairs test because of many missing values at the time point, 3 months. ***P < 0.001; **P < 0.01; *P < 0.05; ns, not significant.
Happonen et al. Arthritis Research & Therapy 2012 14:R15 doi:10.1186/ar3694