Gold binding to red blood cells.

very much higher concentrations.1-4 We have also studied the distribution of gold in blood of patients with rheumatoid arthritis during treatment with sodium aurothiomalate and confirmed these results on the intersubject differences in distribution of gold. We surveyed the patients to determine factors which might affect the distribution of gold. From this survey we have identified smoking as the major factor affecting the uptake of gold by red blood cells. The ratio of the gold concentrations in red blood cells to the plasma concentrations was 0 35 ± 0*07, n = 14 (mean ± standard error) in smokers and 0-028 0-003, n = 23 in nonsmokers.5 The difference was highly significant (p<0.0001), and there was no overlap between the 2 groups. The concentration ofthiocyanate in plasma is markedly elevated by smoking.6 Preliminary studies in vitro indicate that thiocyanate significantly increases gold uptake by red blood cells. Whole blood from 5 healthy, nonsmoking volunteers was incubated with sodium aurothiomalate and varying concentrations of thiocyanate. The concentrations of gold in red blood cells after 24 hours' incubation with 0, 100 FiM, and 500 FM concentrations of thiocyanate were 0-032 + 0.002 ,ug/ml (mean ± SE), 0*084 ± 0*010 ,Lg/ml and 0*32 + 0 05 [Lgfml respectively. This may be the explanation for the increased red blood cell gold uptake in smokers. A manuscript outlining these findings will be presented shortly.