Baseline and interferon-enhanced natural killer cell activity in rheumatoid arthritis.

Natural killer (NK) cell activity against the leukemia cell line K-562 was tested in 45 patients with rheumatoid arthritis (RA) who either had not received any remission-inducing drugs for more than 6 months or had received penicillamine for at least 6 months. Baseline NK cell activity and interferon (IF)-enhanced NK cell activity did not differ from that observed in 45 controls matched for age and sex, and neither NSAID (non steroidal anti-inflammatory drugs) nor penicillamine influenced NK cell activity. There was no correlation between NK cell activity and acute-phase reactants.