Abstract | OBJECTIVE: METHODS: Serum concentrations of IL-18 in ASD patients were compared by enzyme-linked immunosorbent assay (ELISA) with those in patients with other systemic rheumatic diseases and healthy controls. The biologically active mature protein of IL-18 was detected by Western blot analysis with anti-IL-18 antibody and its induction of interferon-gamma (IFNgamma) secretion from IL-18-responding human myelomonocytic KG-1 cells. The inhibitory activity on IL-18 binding to its receptor was determined by 125I-IL-18 binding inhibition assay using the Chinese hamster ovary cell line transfected with a murine IL-18 receptor (CHO-K1/ mIL-18R). RESULTS: Concentrations of serum IL-18 were extremely elevated in patients with active ASD compared with those in patients with rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, polymyositis/dermatomyositis, Sjogren's syndrome, or healthy individuals. Levels of IL-18 were found to correlate with serum ferritin values and disease severity in ASD. Western blot analysis revealed that serum samples from patients with active ASD contained an 18-kd polypeptide of IL-18, corresponding in size to the mature form. Accordingly, the samples were able to induce IFNgamma secretion from KG-1 cells, which was largely abolished by neutralizing anti-IL-18 antibody. However, the level of IL-18 bioactivity was more than 10-fold weaker than the concentration of IL-18 protein measured by ELISA. Serum samples from patients with active ASD showed an inhibitory effect on the binding of 125I-IL-18 to CHO-K1/ mIL-18R cells, and this activity was associated with elevation of IL-18. CONCLUSION: These data indicate that systemic overproduction of IL-18 may be closely related to the pathogenesis of ASD, despite the restriction on its inflammatory activity by IL-18 binding inhibitors such as IL-18BP. The disease activity appears to be determined on the basis of the relative levels of IL-18 and its specific inhibitors.
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Authors | M Kawashima, M Yamamura, M Taniai, H Yamauchi, T Tanimoto, M Kurimoto, S Miyawaki, T Amano, T Takeuchi, H Makino |
Journal | Arthritis and rheumatism
(Arthritis Rheum)
Vol. 44
Issue 3
Pg. 550-60
(Mar 2001)
ISSN: 0004-3591 [Print] United States |
PMID | 11263769
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Glycoproteins
- Intercellular Signaling Peptides and Proteins
- Interleukin-18
- RNA, Messenger
- interleukin-18 binding protein
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Topics |
- Adult
- Arthritis, Rheumatoid
(blood)
- Blood Circulation
- Female
- Gene Expression
- Glycoproteins
(antagonists & inhibitors, blood)
- Humans
- Intercellular Signaling Peptides and Proteins
- Interleukin-18
(blood, genetics)
- Male
- Monocytes
(chemistry)
- RNA, Messenger
(blood)
- Reverse Transcriptase Polymerase Chain Reaction
- Still's Disease, Adult-Onset
(blood)
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