Changes in serum biomarker levels between baseline (week 0) and week 2 of infliximab treatment in the ankylosing spondylitis (AS) patients (n = 8) (A) and psoriatic arthritis (PsA) patients (n = 8) (B) of cohort 1 as well as in the AS patients from cohort 2, who did not have peripheral disease (n = 21) (C). Paired t-tests were performed. Data are represented as mean (standard error of the mean). *P <0.05. hs-CRP, high-sensitivity C-reactive protein; MMP-3, matrix metalloproteinase-3.