Possible explanations for the differences between these findings include haNK cell endogenous expression of IL-2, while our cells were supplemented with 1000 U/ml IL-2, lymphoid versus carcinoma target cells, as well as the 18-h release assays used for the haNK cells, which may allow for detection of longer-term killing potential than our 8-h release assays. The gene discussed is IL2; the disease is carcinoma.