Fifteen patients with metastatic renal cell carcinoma (RCC) were treated by administration of autologous lymphokine-activated killer (LAK) cells given together with systemic administration of interleukin-2 (IL-2). Pulmonary metastases alone were found in 10 cases, pulmonary and mediastinal nodal metastases in 3, and pulmonary and bone metastases in 2. LAK cells, generated by incubation in 700 units/ml of IL-2 for 3-4 days, were intravenously administered once a week. In addition, beginning on the day of the first LAK cell infusion, 3.5 x 10(5) units of IL-2 were intravenously infused once or twice a day with occasional supplementation of 3.5 x 10(5) units of IL-2 on each day of LAK cell infusion. The total number of LAK cells and total amount of IL-2 administered per patient in this study ranged from 0.8 x 10(10) to 6.9 x 10(10) cells and from 10.2 x 10(6) to 74.9 x 10(6) units, respectively. As toxic effects caused by the infusion of LAK cells, headache, shaking chills, fever and leukocytosis were found in all cases. Side effects possibly induced by IL-2 infusion were tolerable fever, fluid retention (body weight gain of 2-3 kg) and eosinophilia. Out of 15 patients, a partial response was observed in 4 patients who had pulmonary metastases alone. One of the 4 patients with a partial response was clinically free of disease after undergoing a thoracotomy for resection of residual lesions, but a brain metastasis was detected 10 months after the thoracotomy. The remaining 3 patients are being closely followed up at present.(ABSTRACT TRUNCATED AT 250 WORDS)