EBV-associated lymphoma in control versus CIK cell–treated mice. SCID mice were injected with low-density CML cells from patient M.R. in matrigel. Groups of mice were treated with autologous CIK cells at 4 and 8 weeks following the injection of the CML cells. At 12 weeks the majority of the mice developed lymphomas that were found to be EBV associated. Two control mice that did not receive CIK cells are shown in the left hand panels. The large arrows indicate the lymphomas. On the right hand panel two mice who received CIK cells at week 4 are shown. No tumors are visible, but the remains of the matrigel can be seen (small arrows).