A method for enhancing the therapeutic effect of cytokine treatment is disclosed. More specifically the present invention relates to a method for administering to a tumor patient a therapeutic dose of cytokine in combination with antibodies directed against the tumor associated antigen carbonic anhydrase IX (CAIX/G250/MN). The improved treatment method is characterized in a significantly reduced cytokine-related toxicity combined with potentiated effectiveness of anti-G250 antibody alone, resulting in a positive therapeutic response with respect to that observed with single anti-tumor agents alone.
