Natural killer augmentation in systemic lupus erythematosus via a soluble mediator derived from human lymphocytes

Seventeen patients with diagnosed systemic lupus erythematosus were studied for natural killer activity and the ability of a human soluble immune-response factor to modify this activity. Defective natural killer activity was found in patients with systemic lupus erythematosus regardless of the stage of disease, medication, or organ system involvement (24.6% versus 47.8% cytotoxicity). After treatment with the immune-response factor, the natural killer activity increased in all patients, with a mean of 47.3% compared with 24.6% before treatment. This product has other immunologic activities and was shown to be free of interferon. The mechanism of action is not yet known, but such an immune-response factor has potential use in the treatment of systemic lupus erythematosus.