Figure 3

Link between circulating tumour necrosis factor (TNF)-α bioactivity and clinical response. Using the ability of TNF-α to stimulate rheumatoid arthritis synoviocytes, TNF-α (5 ng/ml) was combined with 20 μl plasma per well in order to increase the sensitivity of synoviocyte response. Levels of circulating TNF-α bioactivity were estimated with plasma samples obtained before infliximab therapy and separated according to American College of Rheumatology (ACR) clinical response (good or poor) at 54 weeks (n = 42). A good clinical response was defined as an ACR 50 response or better (n = 24).