Natural killer-cell activity and the response to interferons alpha, beta, and gamma in patients with primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is a chronic, life-threatening disorder that is believed to be immunologically mediated. Abnormal immunologic findings have been detected in T suppressor cell activity, B cell responsiveness, and natural kill (NK)-cell function. NK-cell function has been described as low and to be poorly responsive to high concentrations of interferon (IFN). The present study was initiated to determine the response of NK-cell function of patients with PBC to all forms of IFN (alpha, beta, and gamma) at low concentrations. Ten patients were assessed on two occasions approximately 5 months apart. There was a significant decrease in the NK-cell function in a 4-hour assay but only one patient had low NK-cell function after an 18-hour assay. The augmentation of NK-cell activity secondary to 10 and 50 U/ml of IFN-alpha, beta, and gamma was equivalent in the patients and in the control subjects. The relative increase induced by IFN was higher during the 4-hour assay than in the 18-hour assay. Hence, there may be a kinetic impairment of NK-cell function in patients with PBC, but the ultimate lytic activity, and response to the various forms of IFN, are normal.