In acute myeloid leukemia (AML) patients administered with low-dose IL-2 at 16,400 U/kg subcutaneously three times for 18 months, CD3-CD16-CD56bright and CD3-CD16+CD56+ NK cells increased in the blood, and the expression of NKp30 and NKp46 also increased. The gene discussed is IL2; the disease is acute myeloid leukemia.