CORRELATION BETWEEN IL-12 AND IL-2 BLOOD-LEVELS IN THE METASTATIC NEOPLASTIC DISEASE - A POSSIBLE INHIBITORY FEEDBACK-SYSTEM REGULATING THEIR SECRETION

Despite the great importance of IL-2 and IL-12 in activating the antic ancer immune response in humans, cancer related physiopathology of the ir secretion needs to be better investigated. IL-2 blood levels have b een proven to decrease in the advance neoplastic disease, whereas prel iminary data would suggest an enhanced secretion of IL-12 in metastati c cancer patients. This study was performed to analyze IL-2 levels in relation to those of IL-12 in metastatic solid neoplasms. The study in cluded 40 untreated metastatic cancer patients. Serum levels of both I L-2 and IL-12 were measured by ELISA. Abnormally low blood levels of I L-2 and elevated values of IL-12 were observed in 16/40 and in 18/40 p atients, respectively. Moreover, patients with IL-2 deficiency showed significantly higher mean levels of IL-12 than patients with normal va lues of IL-2. This preliminary result, by showing an increased secreti on of IL-12 in advanced cancer patients with IL-2 endogenous deficienc y, would suggest the existance of a possible feedback mechanism operat ing between macrophage release of IL-12 and T lymphocyte secretion of IL-2.