Expression of interleukin-18 in serum,synovial fluid and synovial tissue in patients with rheumatoid arthritis / 中华风湿病学杂志

ABSTRACT

Objective To investigate the expression of interleukin 18 (IL 18) in serum,synovial fluid and synovial tissue of patients with rheumatoid arthritis (RA) and to identify its pathological role in RA.Methods The serum,synovial fluid and synovial tissue were obtained from patients with RA,and samples from patients with osteoarthritis (OA) and from healthy human were used as control groups.Levels of IL 18 protein in serum and synovial fluid were measured by enzyme linked immunosorbent assay (ELISA).Expression of IL 18 mRNA in synovial tissus was determined by semi quantitative reverse transcriptase polymerase chain reaction (RT PCR).The biologic activity of IL 18 in serum and synovial fluid was detected on the basis of IFN ? secretion from IL 18 responding human myelomonocytic KG 1 cells.Expression of iNOS and COX 2 mRNA in synovial tissue was also determined,and productions of NO and PGE 2 in serum and synovial fluid were measured by enzyme reduction method and ELISA.Results Levels of IL 18 protein and biologic activity of IL 18 in both serum and synovial fluid of patients with RA were significantly increased compared with corresponding samples of the two control groups.In addition,the expression of IL 18 mRNA in synovial tissue of patients with RA was also significantly increased compared with samples of the two control groups.Conclusion The over expressed IL 18 may play an important role in the pathogenesis of RA.