Reduction of peripheral blood lymphocytes in patients receiving gold therapy for rheumatoid arthritis.

Peripheral blood lymphocytes were monitored prospectively in 10 patients with rheumatoid arthritis (RA) receiving up to 1 g of sodium aurothiomalate. There was a significant fall in the absolute lymphocyte count from a mean +/- SEM of 1956 +/- 190/mm3 (1.956 +/- 0.19 X 10(9)/l) to 1232 +/- 210/mm3 (1.232 +/- 0.21 X 10(9)/l) (p less than 0.01). The number of of circulating lymphocytes fell in all patients by an amount which ranged between 108/mm3 (0.108 X 10(9)/l) and 1394/mm3 (1.394 X 10(9)/l), with a mean fall of 727/mm3 (0.727 X 10(9)/l). No significant change was noted in the total white cell count or total polymorphonuclear cell count over the same period. In contrast there was no change in the total lymphocyte count in an age and sex matched group of RA patients treated with penicillamine. This previously unreported observation may give new insight into the mechanism of action of gold salts in RA.