Altered thiol status in patients with rheumatoid arthritis.

The thiol status of patients with rheumatoid arthritis is significantly different from that of controls. Plasma thiol levels are lower, albumin thiol reactivity is altered and intracellular thiol levels measured after hemoglobin precipitation are increased. These variations correlate with other indices of disease severity and are one measure of a disturbance in the degree of oxidation of the blood. Penicillamine, in common with other effective therapeutic agents, produces an increase in serum thiol concentration. It causes a greater effect on serum thiol reactivity than other drugs and in particular it increases 'fast reacting' thiol levels without significantly altering the 'slow reacting' thiol level.