Relationship between blood and joint tissue DHEAS levels in rheumatoid arthritis and osteoarthritis

To assess the relationship between blood and tissue steroid levels, cortisol and dehydroepiandrosterone sulphate (DHEAS) were measured by radioimmunoassay (RIA) in blood and joint tissues from a group of patients with RA (N = 29) ranging in age from 26 to 80 years (mean 63, SD: 13) and another group with secondary osteoarthritis (OA; N = 23), ranging in age from 47 to 86 years (mean 66, SD: 9), all of whom were scheduled for surgical correction of joint dysfunction. Seventeen of the RA patients were on steroid treatment at the time of the study. Assessing all the patients together, it was found that the tissue concentrations of DHEAS very closely paralleled the blood levels (r = 0.875; p < 0.001). The mean blood and tissue concentrations of DHEAS were found to be significantly reduced in RA, compared to those in OA (geometric means 540 vs. 2100 nmol/l blood, respectively, and 160 vs. 420 nmol/kg tissue, p < 0.001). Individual data indicated, however, that: (a) 3/29 patients with RA exhibited normal levels; (b) the reduction was more accentuated in those patients on steroid treatment; and (c) 5/23 patients with OA, who were treated for cardiovascular disorders, also had reduced DHEAS levels. Significant differences were not found between the mean cortisol levels in RA and those in OA, nor was there a correlation between the blood and tissue levels of this steroid. The possible influence of reduced DHEAS levels on immune-mediated diseases and/or pathophysiology is unknown, and needs to be investigated.