Tumor necrosis factor-alpha (TNF-α) downregulates gene expression of the myofibroblast marker alpha-smooth muscle actin (α-SMA) and the extracellular matrix protein collagen type I. The mRNA expression of α-SMA (a) and collagen type I (b) was determined for every group (Figure 1) by quantitative real-time polymerase chain reaction. The mRNA level of α-SMA of every group examined was normalized to the housekeeping gene 18S. Data are representative of four (Table 1) independently performed TNF-α ± infliximab (IFX) experiments and TNF-α ± diclofenac (Diclo) experiments with duplicate measurements from each individual patient sample (n = 16 for the 'control' and 'TNF-α 10 ng/mL' groups and n = 8 for all other groups). Results are plotted as fold changes of the respective samples in the control group according to the paired non-parametric Wilcoxon test used for the statistical analysis. *P < 0.05, **P < 0.01, ***P < 0.001.