関節リウマチとロイコトリエン受容体

抄録

Leukotriene B₄(LTB₄) is a metabolite of arachidonic acid and potent chemotactic factors and activators of neutrophils and macrophages. Overproduction of LTB₄ is involved in various inflammatory diseases such as rheumatoid arthritis(RA).
To evaluate the role of LTB₄ receptors in inflammatory arthritis we measured the two types of LTB₄ receptors, BLT1 and BLT2. BLT1 and BLT2 mRNA were detected by reverse transcription polymerase chain reaction (RTPCR) / Southern blot hybridization and in situ hybridization in synovial tissues of 40 patients with RA and 10 patients with OA(Osteoarthritis). The low affinity receptor BLT2 showed stronger expression than the high affinity receptor BLT1 in actively inflamed synovial tissues from patients with RA. Synovial macrophage, fibroblast-like cells and lymphocytes detected BLT2 mRNA in RA synovial tissues containing active inflammation. Then synovial fluid infiltrated leukocytes dominantly expressed BLT1 mRNA in RA.
These results indicate that LTB₄ effects via BLT1 on synovial fluid leukocytes and via BLT2 on synovial macrophages, fibroblast-like cells and lymphocytes in RA synovial tissues. No BLT antagonists are yet available for clinical use including RA therapy. More further works are needed about lipoxygenase system and inflammatory arthritis such as RA.