Differential effects of interferon-alpha 2 and interleukin-2 on natural killer cell activity in patients with acquired immune deficiency syndrome.

Natural Killer (NK) cell activity of peripheral blood mononuclear cells (PBMC) against K562 myeloid cells was studied in six normal heterosexual men and six patients with acquired immune deficiency syndrome (AIDS). The mean NK cell activity in six patients with AIDS was 28.74 +/- 6.82% (SEM) compared with 47.24 +/- 7.26% in six normal heterosexual men (p less than 0.10). PBMC obtained from these subjects were incubated overnight in complete medium alone, complete medium supplemented with interferon-alpha 2 (IFN-alpha 2), complete medium supplemented with interleukin-2 (IL-2), and complete medium supplemented with both IFN-alpha 2 and IL-2. Incubation of PBMC with IFN-alpha 2 enhanced the NK cell activity significantly (73.07 +/- 4.22%, p less than 0.025) in normal heterosexual men, but not in patients with AIDS (38.22 +/- 7.10%, p greater than 0.05). In contrast, IL-2 significantly enhanced NK cell activity in both patients with AIDS (57.16 +/- 8.4%, p less than 0.05) and normal heterosexual men (71.58 +/- 5.87%, p less than 0.05). When PBMC from both groups of subjects were incubated with both IFN-alpha 2 and IL-2, the NK cell activity increased to levels higher than those seen with either IFN-alpha 2 or IL-2 alone. These results suggest that IL-2 is capable of augmenting in vitro NK cell-mediated cytotoxicity with cells from AIDS patients.