122 MRCC patients were treated by monthly intralymphatic injections (containing a mean of 573 IL-2 U and 26 Ψ 10 6 LAK cells) and i.m. administration of IFN and TF; 71 patients also received a 3-day cycle of monthly IL-2 inhalations with a mean of 998 daily U. MRCC cases not treated by immunotherapy (n β«Ψβ¬ 89) represent our historical controls. Adverse clinical side effects related to treatment were negligible. CR (n β«Ψβ¬ 11) and PR (n β«Ψβ¬ 13) were noticed in 24/122 patients. Of 24 responding patients, 17 resumed progression, whereas 7 remain in remission 11-69 months later. The overall median survival of treated patients (28 months) was 3.5-fold higher than the median survival of historical controls (7.5 months), and a Kaplan-Meier curve showed 25% survival 11 years after the beginning of immunotherapy. Apparently, the addition of IL-2 by inhalation improved survival. The present immunotherapy protocol appears to be efficacious, safe, devoid of adverse side effects, far less costly than others and able to offer a good quality of life to MRCC patients; if confirmed in a multicenter trial, it could set the basis for developing lowdose immunomodulatory treatments.