Immunologic effects of recombinant interferon-gamma in patients with renal cell carcinoma

Immunologic and antitumor effects of human recombinant interferon-gamma were studied in patients with renal cell carcinoma. A daily dose of 6 to 12 x 10(6) units/m2 of interferon-gamma was given by intravenous drip infusion or intramuscular injection to nine patients over a period varying from two to 16 weeks. Antibody-dependent cell-mediated cytotoxicity and OKIa1-positive monocytes count increased significantly after the therapy was started. Interferon-gamma transiently increased OKT3- and OKT4- positive lymphocyte count. Tumor regression was not observed when clinical response was evaluated in seven patients. Two others, who had no measurable metastases, were not evaluated, because interferon-gamma were given to them as post-operative adjuvant therapy. Our results indicate that interferon-gamma stimulated monocytes and enhanced cell-mediated cytotoxicity; they also suggest the necessity of combining monoclonal antibodies and other biological response modifiers that effect tumor-associated antigens.