Induction of cytotoxicity of the renal hilar lymph nodes by pedal subcutaneous administration of interleukin-2 in patients with renal cancer. The authors attempted to increase the cytotoxicity of the renal hilar lymph nodes in ten patients with renal cell carcinoma by administration of recombinant interleukin-2 (IL-2) into the subcutaneous tissue of the instep. A total of 5000 to 21,000 units was given over 3 to 12 preoperative days. Mononuclear cells separated from the lymph nodes excised from the renal hilum at surgery served as the effector cells. Fresh autologous tumor cells and three cultured cell lines, K562, Raji, and ACHN, served as the target cells. Cytotoxicity was measured by a chromium-releasing assay. The results showed that the mononuclear cells from the lymph nodes of the patients given IL-2 became cytotoxic to all target cells. Surface markers of lymphocytes in the lymph nodes were unchanged. Peripheral blood lymphocytes showed increased cytotoxicity only against Raji cells. Adverse effects were mild or moderate and included local redness, high fever, liver dysfunction, and toxic erythema. 