SYNOVIAL-FLUID CYTOKINES IN PATIENTS WITH RHEUMATOID-ARTHRITIS OR OTHER ARTHRITIC LESIONS

The synovial fluid (SF) of rheumatoid arthritis (RA) patients contains a mixture of inflammatory mediators. In order to determine whether ce rtain cytokine patterns locally in the joint are specifically related to the chronic inflammation in RA, the concentrations of interleukin ( IL)-1 alpha, IL-1 beta, IL-6, IL-10, transforming growth factor-beta ( TGF-beta), tumour necrosis factor-alpha (TNF-alpha) and IgG2b-inducing factor (IgG2bIF) were measured in SF from 22 patients with RA and 22 patients with other types of arthritic lesions. High levels of IL-10, latent and active TGF-beta and the presence of IgG2bIF are significant ly correlated with RA when corrected for age. As these factors have th e capacity to promote antibody production, they might contribute to th e maintenance of local antibody production in RA synovial tissues. All RA-SF samples contained detectable levels of IL-10 and all except one contained IL-1 beta, while concentrations in several non-RA-SF sample s were below detection limits. IL-6 and TGF-beta were present in all S F samples from both RA and non-RA patients. The presence of IgG2bIF wa s strongly correlated with high levels of IL-10 and IL-1 beta in SF. H owever, no distinct cytokine profile specific for the chronic inflamma tion characteristic of RA was found.