Rheumatology Advance Access originally published online on December 13, 2005
Rheumatology 2006 45(2):229-230; doi:10.1093/rheumatology/kei196
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© The Author 2005. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org
LETTER TO THE EDITOR |
Sequential synovial fluid sampling suggests plasma and synovial fluid IL-6 vary independently in rheumatoid arthritis
Academic Rheumatology, University of Bristol, Bristol Royal Infirmary and 1 Henry Wellcome Laboratories for Integrated Neuroscience and Endocrinology, University of Bristol, Bristol, UK
Correspondence to: M. G. Perry, Academic Rheumatology Unit, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK. E-mail: mark.g.perry@bristol.ac.uk
| The first 10% of the full text of this article appears below. |
SIR, Inflammatory cytokines, including interleukin-6 (IL-6), are raised in rheumatoid arthritis (RA). Single paired daytime samples show that the IL-6 and TNF-
concentrations in synovial fluid exceed blood concentrations during the day [13], and these and other data suggest that joints are the source. Recent data have shown that plasma IL-6 in RA follows a circadian pattern with a peak at 6 a.m. [4]. If IL-6 is generated inside joints and diffuses into plasma, it might be expected that the synovial fluid IL-6 concentration