A non randomized pilot study has been undertaken to evaluate the feasibility of local immunotherapy (IT) of recurrent glioblastoma multiforme (GM) by continuous intracerebral perfusion of recombinant interleukin-2 (rIL-2, Eurocetus) with and without lymphokine activated killer (LAK) cells. At time of surgical removal of the tumor, a catheter was implanted in the cavity left by tumor debulking allowing continuous perfusion of rIL-2. Five patients received 18 x 10(6) IU/day or rIL-2 for five days. At days 1, 3, and 5 after surgery, rIL-2 perfusion was briefly interrupted for the injection of LAK cells. Eight other patients received rIL-2 alone, either 24 x 10(6) IU/day (five patients) or 54 x 10(6) IU/day (three patients). Capillary leak syndrome, which is the main side effect of systemic infusion of rIL-2, was never observed, but local immunotherapy induced fever, confusion, and cerebral edema in all patients. Despite local IT, tumor progression was diagnosed by CT scan 4 to 12 weeks after the treatment.