Detection of impaired mitogen responses in autologous whole blood of cancer patients using an optimized method of lymphocyte stimulation.

Mitogenic lymphocyte stimulation with six concentrations of phytohemagglutinin (PHA) was compared in 60 patients with advanced or metastatic cancer and 30 age- and sex-matched healthy controls using an optimized whole blood method. Since the method is simple and the number of technical variables relatively small, a "normal" range of PHA responsiveness expressed in absolute cpm, could be established. It is thus possible to directly compare results from different laboratories. A markedly reduced lymphocyte stimulation was found in cancer patients compared to controls, although leukocyte and lymphocyte counts were almost "normal". The implications of this finding are discussed with regard to immunosuppression by the tumor and previous chemotherapy.