Intracellular and extracellular sulphydryl levels in rheumatoid arthritis.

We detected no difference in the reduced glutathione content of erythrocytes obtained from patients with rheumatoid arthritis (RA) and controls. The stability of glutathione to oxidative stress (cumene hydroperoxide) was also the same. Although measured in the erythrocyte, our results indicate that changes in intracellular reduced glutathione are not involved in the aetiology of RA. Serum from patients with RA had a significantly reduced (p less than 0.01) sulphydryl (SH) concentration (415 +/- 89 (SD) mumol/l) compared with controls (583 +/- 74 mumol/l). This was also valid if the SH groups were expressed per gram of protein. Serum and synovial fluid from RA patients contained similar levels of SH groups (mumol/g protein).