Seventeen patients with diagnosed systemic lupus erythematosus were studied for natural killer activity and the ability of a human soluble immune-response factor to niodify 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.Systemic lupus erythematosus (SLE) has been associated with numerous immunologic aberrations, including abnormalities in cell-mediated immunity and antibody function and formation (1-2). However, much of these data are controversial, and many authors have not supported these conclusions. More recently, data suggesting an abnormality in cytotoxic function have been reported ( 3 ) , and several investigations have demonstrated a deficiency in suppressor T cells in patients with SLE (4-5). While it is not entirely clear what perturbations of immune function are important in this disease, current information strongly suggests abnormalities in immunoregulation either through cell-to-cell interaction or through soluble mediators that lead to autoantibody formation.There is a great deal of interest about the phenomenon of spontaneous cell-mediated cytotoxicity or natural killer activity as a host defense against tumors, viruses, and foreign tissue (6-9). There have been several recent published reports of decreased natural killer activity in patients with systemic lupus erythematosus (10-13).We have previously reported on a concanavalin A-induced soluble product of human lymphocytes, which we have called soluble immune response factor. It is suppressive in nature and capable of restoring the suppressor defect in systemic lupus erythematosus (14). This factor also appears to have some additional augmenter activity.In the present study we investigated the natural killer activity of peripheral blood lymphocytes from patients with systemic lupus erythematosus and the effects of our lymphocyte product on natural killer activity.
MATERIALS AND METHODSPatients. Seventeen patients with systemic lupus erythematosus were evaluated. There were 4 males and 13 females, ranging in age from 15 to 52. Six were not receiving medications. (Two of them were newly diagnosed as having active disease.) Eleven were receiving steroids, from 5-45 mg of prednisone daily. The patients were not receiving antimalarial medication or aspirin; 1 patient was taking Cytoxan. All patients met the criteria of the American
