Augmentation of lymphokine-activated killer cell activity in patients with gastrointestinal cancer

Adoptive cellular immunotherapy with lymphokine-(interleukin 2) activated killer (LAK) cells is not as successful in patients with gastrointestinal cancer as with other tumour types. This may be because the cytotoxic capacity of LAK cells from such patients is suboptimal. In this study we have sought to augment this activity by stimulating the lymphocytes with recombinant human interferon-gamma (r-HuIFN-gamma) in addition to interleukin 2 or by depleting the lymphocytes of adherent suppressive mononuclear cells. Both procedures augment LAK activity in gastrointestinal cancer patients but adherent cell depletion results in fewer cells being available for adoptive cellular immunotherapy. No further augmentation of LAK activity of adherent cell depleted cells could be accomplished by addition of r-HuIFN-gamma. Co-stimulation of unfractionated peripheral lymphocytes with r-HuIFN-gamma is the preferable procedure for the generation of LAK cells for adoptive cellular immunotherapy in patients suffering from gastrointestinal cancer.