Circulating bioactive TNF in rheumatoid arthritis patients treated with infliximab: link to clinical response
© The Author(s) 2003
Received: 14 January 2003
Published: 24 February 2003
Infliximab is an anti-tumor-necrosis-factor (anti-TNF) antibody used for the treatment of rheumatoid arthritis.
To clarify heterogeneity in patient response, a bioassay was established to measure functional circulating tumor necrosis factor (TNF).
Culture of TNF activated synoviocytes with plasma samples before and after infliximab treatment showed an increased production of IL-6 that was strongly reduced by treatment. This pattern was associated with a good clinical response, and bioactive TNF levels detected with this bioassay were correlated with TNF levels measured by ELISA. This was not observed in patients with a poor response. The functional circulating bioactive TNF was significantly (P < 0.001) more elevated in subset with a good biological response than bad responders. No correlation was observed with levels of soluble receptors.
This result suggests the importance of systemic bioactive TNF in such response.