Insensitivity to interferon of NK cells from patients with systemic lupus erythematosus.

Natural cytotoxicity (NK) by fresh E-rosette-negative (ER-) cells from normal donors was increased after overnight incubation with purified IFN alpha and with supernatants containing IFN gamma. ER- cells from 61% of 23 patients with systemic lupus erythematosus did not show increased cytotoxicity after treatment with IFN alpha. Similarly, ER- cells from nine of 18 patients that were treated with IFN gamma-containing supernatants failed to show increased cytotoxicity. The patients who did not show enhanced cytotoxic responses to IFN had higher mean indices of disease activity than responding patients.