Suppressor cells in melanoma and lung cancer: correlation with the clinical stage

Mononuclear blood cells from 40 healthy donors, 25 patients with melanoma and 35 patients with lung cancer were tested for suppressor cell activity and response to phytohemagglutinin (PHA). The suppressor cell activity was measured by determining the ability of Mitomycin C (MMC)-treated mononuclear cells from patients and controls to suppress the in vitro response of responder cells to PHA. Mononuclear cells from one healthy donor were stored in liquid nitrogen for use as responder cells. Indomethacin-sensitive suppression was also measured. In both groups of patients the mean values of suppressor cell activity in co-culture were higher than those in control group. When patients were subdivided in groups according to the clinical stage, the level of suppressor cell activity increased with the stage. Indomethacin-sensitive suppression was detected in some patients but the differences between patient and control groups were not statistically proved. An inverse relationship was observed between indomethacin-sensitive suppression and the PHA response.