This study investigated the presence of arachidonic acid metabolites, (leukotriene B₄, leukotriene C₄ and prostaglandin E₂) in the serum, synovial fluid and synovium of rheumatoid arthritis patients (RA). We obtained the serum, synovial fluid and synovium from 16 female patients with RA during knee operations. Leukotriene B₄ (LTB₄), leukotriene C₄ (LTC₄) and prostaglandin E₂ (PGE₂) were detected by RIA analysis.
In the patients administered steroids, a positive correlation was found between the concentrations of LTB₄ and PGE₂ in the synovium. In the patients not administered steroids, significant correlations were found between the concentrations of LTB₄ in the synovium and serum, and also between the concentrations of LTB₄ and LTC, in the synovium.
The levels of immunoglobulins and LTB₄ in the serum were determined and a significant correlation was found between the content of IgG and the concentration of LTB₄.
In the serum, the concentration of LTB4 was elevated in RA patients relative to the control normal subjects, and the difference was statistically significant. In conclusion, these data suggest that LTB₄ in the serum reflects the concentration of LTB₄ in the synovium.