Improvement in peripheral blood lymphocyte response to concanavalin A and pokeweed mitogen during gold treatment of rheumatoid arthritis

Blood monocyte elastolytic activity enhanced by immune complex stimulation in patients with rheumatoid arthritis and normal controls. Effect of aurothiomalate or D-penicillamine

Blood monocyte elastolytic activity in patients with rheumatoid arthritis and in normal controls was studied by a new in vitro technique. The enzyme activity of live cells was measured by soluble [3H]elastin hydrolysis first under basic conditions and then after immune complex stimulation. The cells from patients had a higher elastolytic potential than cells from controls (p less than 0.02) and responded to smaller amounts of immune complex (p less than 0.01), even in patients treated with D-penicillamine or aurothiomalate. Treatment of normal monocytes in vitro with aurothiomalate did not influence the elastolytic response. These findings indicate that monocytes from patients with rheumatoid arthritis have an enhanced elastolytic activity compared with cells from normal controls and may invoke greater tissue damage on immune complex stimulation.

The effect of cyanide on the uptake of gold by red blood cells

Cyanide markedly increased the rate of uptake of gold by red blood cells when incubated with sodium aurothiomalate, a polymeric gold complex. Thiocyanate had no significant effect on gold uptake. The effect of cyanide was demonstrated to be due to the conversion of aurothiomalate to the complexion, aurocyanide, which is rapidly taken up by red blood cells. At a low ratio (1:20) of cyanide to aurothiomalate, cyanide appeared to act as a shuttle to carry gold into red blood cells. Tobacco smoking is known to increase the concentrations of gold in red blood cells in patients treated with aurothiomalate. The present data indicate that this effect of smoking is most likely due to cyanide inhaled in tobacco smoke and not to thiocyanate, a circulating metabolite of cyanide. An effect of cyanide on the uptake of polymeric gold complexes to target cells such as polymorphonuclear leukocytes and monocytes is suggested.

Immunosuppressive actions of gold salts

In rheumatoid arthritis both lymphocyte-mediated and antibody-mediated immune reactions are important for the inflammatory lesions. In vivo activated B lymphocytes/plasma cells, T lymphocytes and monocytes/macrophages (Mo) are intimately involved in the disease process. Several clinical observations suggest an immunosuppressive action of gold salts. In humans, gold salts interfere with a number of Mo functions in vitro, including cellular interactions between Mo and T lymphocytes. Some workers have shown that the activation of human T lymphocytes is inhibited by gold salts, most probably secondary to an inhibition of Mo-T cell cooperation. Recent experiments indicate that gold salts also affect the in vitro differentiation of human B lymphocytes in response to polyclonal activators. Both the gold atom and the SH group seem to be important for the immunosuppressive actions of gold salts.