Leukotriene B4, a mediator of inflammation present in synovial fluid in rheumatoid arthritis

Leukotriene B4 (LTB4), generated from arachidonic acid following lipoxygenase activity by a variety of inflammatory leucocytes, has been shown to be present in synovial fluid from patients with active rheumatoid arthritis. It does not persist as such, being converted to less active metabolites. The role of LTB4 as one of the natural mediators of inflammation is discussed.