The study aims were to assess the response of peripheral blood lymphocytes (PBL) of cancer patients to exogenous Interleukin 2 (IL 2) either by PHA-prestimulated or non PHA-prestimulated PBL, and to carry out preliminary experiments for a direct quantitative evaluation of endogenous IL 2 production by PBL cultures of cancer patients in order to define the actual role of IL 2 in the disease. Analysis of PBL subsets was also carried out with monoclonal antibodies in a selected group of patients. A total of 134 patients entered the study. Cancer sites were: larynx 32, breast 36, lung (NSC) 24, colorectal 17 and gynecologic 25. In the former 3 cancer sites staging showed localized or only locally advanced disease, and in the last 2 sites disseminated disease. Our results provided evidence that cancer patients exhibit a T-cell functional immunodepression, which progresses during tumor growth, so that the localized disease shows a low-grade defect, and advanced disease a high-grade defect. Our data also clearly suggested that the factor involved with a primary role in this functional immune impairment is the IL 2 deficiency. A perspective may be drawn on the therapeutic administration in vivo of IL 2 and IL 2-activated lymphokine-activated killer cells in controlled clinical trials of selected groups of cancer patients
