In 1999 an experiment was carried out by Walker, Walker, Ogston, et al. upon a number of cancer patients. Guided imagery was used to increase immune response and it was shown that the more vivid the imagery used by the experimental group, the higher the NK (natural killer) and LAK (lymphokine activated killer) white blood cell activity after chemotherapy. This points to imagery on its own having an effect on immune response. Hypnotherapy is widely acknowledged as a tool to create the most vivid of imagery.
