Interleukin-6 in synovial fluid and serum of patients with rheumatoid arthritis and other inflammatory arthritides.
Interleukin-6 (IL-6), also called 26-kd protein, hybridoma plasmacytoma growth factor, beta 2-interferon, or B cell stimulatory factor 2, is a recently described human cytokine with multiple growth and differentiation activities. Using a very sensitive bioassay based on the growth factor activity of this protein for B cell hybridomas, we found that IL-6 activity was significantly elevated in synovial fluid from patients with rheumatoid arthritis (RA) or other inflammatory arthritides, as compared with that in a group of patients with osteoarthritis. Moreover, IL-6 was detected in about one-third of the serum samples from patients with RA. In the latter group, we found a significant correlation between serum IL-6 activity and serum levels of C-reactive protein, alpha 1-acid glycoprotein, alpha 1-antitrypsin, fibrinogen, and haptoglobin, which indicates that IL-6 is related to disease activity in patients with RA.
Houssiau
F A
FA
Experimental Medicine Unit, Université Catholique de Louvain, Brussels, Belgium.
Devogelaer
J P
JP
Van Damme
J
J
de Deuxchaisnes
C N
CN
Van Snick
J
J
D001168:Arthritis / Q000097:blood / Q000378:metabolism*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000378:metabolism*; D006133:Growth Substances / Q000378:metabolism; D006801:Humans; D006825:Hybridomas / Q000378:metabolism; D015850:Interleukin-6; D007378:Interleukins / Q000097:blood / Q000378:metabolism*; D013582:Synovial Fluid / Q000378:metabolism*
D006133:Growth Substances; D015850:Interleukin-6; D007378:Interleukins