[Long-term immunological study on postoperative adjuvant treatment with interferon-gamma in patients with renal cell carcinoma who underwent nephrectomy].

Previously, we reported the short-term immunological effects of postoperative adjuvant interferon-gamma (IFN-gamma) administration to renal cell carcinoma patients as determined by three-color flow cytometry. We now report the results of a long-term study on a larger number of subjects. Thirty-three patients with renal cell carcinoma received a prophylactic intramuscular injection of IFN-gamma (300 x 10(4) units per week) after nephrectomy. We evaluated immunological changes by measuring peripheral blood lymphocyte subsets including activated cytotoxic T lymphocytes (ACTL), cytotoxic T lymphocytes (CTL), activated suppressor T lymphocytes (ASTL), helper T lymphocytes (HTL), activated suppressor-inducer T lymphocytes (AITL), and suppressor-inducer T lymphocytes (SITL). We also estimated the natural killer (NK) activity by a cytolytic test. All 33 patients were examined for at least 12 months after the start of IFN-gamma injection, and 18 patients were examined for 30 months including the 6-month period following discontinuation of IFN-gamma injection. We found significant enhancement of the ACTL subset from the second week to the sixth month after the start of IFN-gamma injection. On the other hand, we found a significant decrease in the percentage of the HTL and SITL subsets for a long time after the start of injection. NK activity significantly increased throughout the period of administration, and it continued to increase for six months after discontinuation of IFN-gamma injection.