VARIOUS FUNCTIONS OF PBMC FROM COLON-CANCER PATIENTS ARE NOT DECREASED COMPARED TO HEALTHY BLOOD-DONORS

The immune surveillance hypothesis suggests impaired immune responses to participate in development of cancer This may partly be due to incr eased amounts of PGE(2) and histamine, which inhibit cellular immunity . These effects are mediated by cAMP, which is increased and thereby m ay down-regulate IL-2 and its receptor proteins in T helper cells. The proliferative responses and IL-2 synthesis of PBMC have earlier been shown to be reduced in patients with colon cancer. Recently immune mod ulating agents have been demonstrated to increase the proliferative re sponse of PBMC in vitro. probably by inhibition of adenylate cyclase a ctivity and induction of IL-2 mRNA expression. We have therefore studi ed the proliferative responses of PBMC from colon cancer patients to P WM and tested the effect of immune modulating agents, such as Serotoni n, Sumatriptan, and Buspirone on these PBMC. We found no difference in levels of intracellular cAMP, IL-2 mRNA expression, IL-2R mRNA expres sion, or proliferative responses of PBMC from colon cancer patients co mpared to healthy blood donors. There was no effect of the immune modu lating agents on PBMC from colon cancer-patients.