Interferon production by peripheral blood leukocytes of patients with acute myeloid leukemia.

The ability of peripheral blood leukocytes (PBL) of 13 selected patients with acute myeloid leukemia (AML), and of 10 healthy subjects to produce interferon (IFN) spontaneously and after in vitro induction was tested. Spontaneous IFN production was detected in supernatants of PBL cultures of healthy subjects but was not present in cultures of leukemic cells (leukocytes density 1 x 10(6) ml). After induction with Newcastle disease virus (NDV) PBL cultures from 5 patients with AML exhibited a low IFN response, while in others IFN titers were similar to controls. The IFN titers induced with lipopolysaccharide (LPS) were lower in leukemic cells than those detected in control cells. The absence or low IFN levels after induction with phytohemagglutinin (PHA) correlated with very small numbers of normal lymphocytes in blood of leukemic patients.