The in vivo effect of triethylphosphine gold (auranofin), sodium aurothiomalate and azathioprine on natural killer cell activity of patients with rheumatoid arthritis.

Natural Killer (NK) cell activity was measured in 80 patients with rheumatoid arthritis (RA) grouped according to medication into 1) controls not in remission-inducing therapy, 2) patients treated with oral gold (auranofin), 3) parenteral gold (sodium aurothiomalate) and 4) azathioprine. Baseline, interferon (IF)-enhanced and interleukin 2 (Il-2)-enhanced NK cell activity of patients in the two gold groups did not differ from that of controls, while NK cell activity before and after exposure to IF and Il-2 was significantly suppressed in patients on azathioprine (p less than 0.01). The percentage of Large Granular Lymphocytes did not differ in the four groups while the percentage of Leu 11 positive cells and the total number of lymphocytes were significantly lower in the azathioprine group. Sixty out of 80 patients received nonsteroidal anti-inflammatory drugs (NSAID), whereas 20 did not. A comparison of these two groups showed no influence of NSAID on NK cell activity.