Figure 2

Pattern of plasma tumour necrosis factor (TNF) bioactivity in rheumatoid arthritis (RA) patients and healthy individuals. Using the ability of TNF-α to stimulate RA synoviocytes, TNF-α (5 ng/ml) was combined with increasing concentrations of plasma from RA patients (0–20%). (a) Four RA plasma samples were obtained before infliximab therapy. (b) RA plasma samples (n = 2) were used at 10% dilution. IL-6 production was measured by ELISA in 48-hour supernatants.