Thirty-one patients with metastatic renal cell carcinoma were seen at the Centre Léon Bérard from October 1987 to October 1988. According to our protocol, 11 were excluded leaving 20 in the study. The median age was 55 years (range 36 to 79 years). The median number of metastases was 9 (range 2 to 29) and the median number of metastatic sites was 3 (range 1 to 4). Seventeen patients received a continuous infusion of recombinant interleukin-2 (rIL-2) of 3 x 10(6) U/m2/day, on days 1 to 5, with lymphapheresis on days 7 to 10 and IL-2 + LAK on days 11 to 15. Three patients received IL-2 alone. The clinical toxicity of IL-2 was as expected (100% fever, 88% erythema, 88% vomiting, 87% weight gain, 76% oliguria, 76% diarrhoea, 70% pruritus, 70% weakness, 41% severe hypotension, 41% acute renal failure, 33% disorientation, 23% respiratory distress, 12% ventilation and 5% coma) with no toxic deaths. Other toxicity was mild (median platelet nadir was 93,000 and median nadir of Hb 8.1 g/dl) except for the creatinine level which was found to be between 200 and 400 mumol/l in 45% of the courses and over 400 mumol/l in 24% of the courses. Eight capillary leak syndromes were observed. Among the three patients receiving IL-2 alone, one PD, one SD and one early toxicity were recorded. Among 15 evaluable patients receiving IL-2 + LAK, three had PR (20%) and two mixed response (PR and progression before 2 months); two had stable disease and eight had progression. No clinical or biological factor was able to predict response. However, the five objective responses were observed among the eight patients with a capillary leak syndrome. Lymphocyte peaks or platelet nadir were not related to response in this group of patients. The median number of harvested mononuclear cells was 9.8 x 10(10) and the median number of mononucleated cells reinjected was 5.9 x 10(10).