Abstract
Natural cell-mediated cytotoxicity (CYT) was determined using whole blood samples from patients with the acquired immunodeficiency syndrome (AIDS) and AIDS related complexes (ARC) and correlated to the proportion and absolute number of natural killer (NK) cells as determined by monoclonal antibodies Leu 11 or NKH.1 and flow cytometry. Mean percent CYT was significantly lower in AIDS and ARC patients compared to that of normal controls, and the defect observed in these patients was not due to fewer NK cells or decreased efficiency in binding to target cells. Kinetic analysis of CYT showed that NK cells from AIDS or ARC patients lysed fewer cells than NK cells from normals. NK cells in these patients are in a less active state or with decreased recycling. Blood samples from the majority of patients with AIDS or ARC were refractory to the stimulatory effects of in vitro additions of interferon alpha (IFNA), interferon gamma (INFG), or interleukin 2 (Il 2) on CYT. Some AIDS/KS patients receiving in vivo IFNA had increased CYT after therapy, and patients receiving in vivo IFNG became responsive to IFNG. Humoral elements may be responsible in part for the reduced CYT observed in the patient groups. Elevated serum immunoglobulins and circulating immune complexes correlate inversely with CYT. Both factors inhibitory and stimulatory to CYT were present in fractionated plasma from an ARC patient. Capping studies suggest that there are alterations in membrane receptor mobility which correlate to diminished functional responses in AIDS and ARC patients.