[Dynamics of interleukin (IL)-18 in serum, synovial fluid and synovial membrane in the patients with rheumatoid arthritis].
OBJECTIVE
IL-18 is a novel cytokine that plays an important role in the Th1 response. The aim of this study is to investigate the dynamics of IL-18 in serum, synovial fluid and synovial membrane in the patients with rheumatoid arthritis.


METHODS
The serum, synovial fluid and synovial membrane were obtained from RA patients at operation. The levels of IL-18 in the serum and synovial fluid were measured by ELISA. We then examined the expression of IL-18 in synovial tissues using anti-human IL-18 monoclonal antibody in immunohistochemical study.


RESULTS
The levels of IL-18 in serum and synovial fluid in RA patients were 193.7 +/- 109.7 pg/ml and 258.8 +/- 238.0 pg/ml, respectively. Compared with OA patients and normal volunteers, the level of IL-18 in RA patients was higher in both serum and synovial fluid. (P < 0.05) In synovial membrane, the cells positive for anti IL-18 antibody were confirmed not only in RA (n = 26) but also in OA (n = 7) patients. The positive cells were the synovial lining cells, macrophages, fibroblasts and endothelial cells. However, a large number of positive cells were demonstrated in synovial tissues in RA compared with OA patients.
Munakata
T
T
Department of Orthopaedic Surgery, School of Medicine, Iwate Medical University, Morioka-city.
Uzuki
M
M
Shimamura
T
T
Sawai
T
T
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D005260:Female; D006801:Humans; D020382:Interleukin-18 / Q000032:analysis / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000276:immunology; D013582:Synovial Fluid / Q000378:metabolism*; D013583:Synovial Membrane / Q000166:cytology / Q000378:metabolism*; D018417:Th1 Cells / Q000276:immunology
D020382:Interleukin-18