Interleukin-2 production in head and neck cancer patients

Interleukin-2, a lymphocyte-produced hormone or lymphokine, is required to support proliferation of antigen-triggered T lymphocytes and cytotoxic T cells that are considered essential elements for host tumor control. We have addressed the question of whether interleukin-2 production is altered in head and neck cancer patients, a group that is frequently immunosuppressed. Interleukin-2 production was measured by the tritium-labeled thymidine CT6 assay on the supernatants of peripheral blood lymphocytes of head and neck cancer patients and controls after 24 hour stimulation with phytohemagglutinin. The mean levels of interleukin-2 produced were 127 units (range 3 to 336 units) in the head and neck cancer patients versus 125 units (range 26 to 307 units) in the control group (not statistically significant). There were no significant differences in mean interleukin-2 values between cancer patients with stages I and II or III and IV disease compared with the control subjects. Twenty-seven percent of the cancer patients had interleukin-2 levels below the 10th percentile cutoff point (p = 0.015). The lymphocyte proliferative response to phytohemagglutinin was significantly depressed in the head and neck cancer patients compared with the control subjects. This did not correlate with interleukin-2 production abnormalities, except in patients with advanced disease, in whom there was a borderline correlation between phytohemagglutinin response and interleukin-2 production (correlation coefficient 0.23, p = 0.05). We conclude that the commonly observed depressed T-cell proliferative response to phytohemagglutinin in head and neck cancer patients is not explained by impaired interleukin-2 production.