Increased estrogen formation and estrogen to androgen ratio in the synovial fluid of patients with rheumatoid arthritis.

OBJECTIVE: It has been proposed that physiologic levels of estrogens stimulate immune responses whereas androgens suppress inflammatory reactions. Thus, prevalence of synovial androgens relative to estrogens would be favorable in rheumatoid arthritis (RA). We investigated synovial fluid (SF) concentrations of several estrogens and androgens and conversion products of the sex steroid precursor dehydroepiandrosterone (DHEA) in supernatants of mixed synoviocytes. METHODS: SF steroid concentrations were measured by high performance liquid chromotography and mass spectrometry in 12 patients with RA and 8 subjects with traumatic knee injury (noninflammatory controls). Conversion of DHEA to downstream hormones was measured by thin-layer chromatography and phosphorimaging detection in 3 patients with RA and 3 patients with osteoarthritis (OA). RESULTS: Overall, SF concentration of free estrogens tended to be higher in RA patients versus controls (p