Serum Interleukin-6 Level is a Sensitive Parameter of Disease Activity in Rheumatoid Arthritis.
In rheumatoid synovium, interleukin-6 (IL-6) is the most abundantly expressed cytokine. Therefore, we investigated whether serum IL-6 levels could be clinically useful parameters of disease activity in rheumatoid arthritis (RA). The serum IL-6 levels were measured by enzyme-linked immunosorbent assay. The IL-6 levels were significantly higher in sera from patients with RA (n = 108, 13.3 +/- 14.0 pg/mL) than in those from the normal controls (n = 10, < 3.13 pg/mL). The IL-6 levels significantly correlated with conventional parameters, such as the Lansbury index, joint score, erythrocyte sedimentation rates, and C-reactive protein. In addition, the serum IL-6 level was useful to determine clinical remission. Advantages of serial measurement of IL-6 were observed in two cases. These findings suggested that the serum IL-6 level may be clinically useful as a sensitive parameter of disease activity in RA.
Sugiyama
E
E
First Department of Internal Medicine (E.S., A.K., F.H., T.H., H.T., M.K.), Toyama Medical and Pharmaceutical University, Toyama, and Internal Medicine (N.A.), Takaoka City Hospital, Takaoka, Japan. This work was in part supported by the Japan Research Foundation for Clinical Pharmacology.
Kuroda
A
A
Hori
F
F
Hori
T
T
Taki
H
H
Arai
N
N
Kobayashi
M
M