Introductory statement: proceedings of Conference on Public Health Implications of Components of Plastic Manufacture.

In patients with advanced head and neck squamous cell carcinoma (HNSC), evidence of cellmediated immunity and monocyte functional abnormalities has been reported. We studied the production of interleukin 1 beta (IL-lbeta) and interleukin 6 (IL-6) by peripheral blood monocytes from 22 patients with HNSC (12 larynx and ten oral cavity cancers) in comparison with monocyte cytokine production of age-matched healthy subjects. Pure monocytes were incubated with and without lipopolysaccarides (LPS) (10 1tg ml-') for 4 h at 37C and IL-Ibeta and IL-6 concentrations were determined in supernatants by specific ELISA. There was no significant difference in IL1beta levels in monocyte supernatants from cancer in comparison to control subjects; conversely, a higher IL-6 production by unstimulated and LPS-activated cells from HNSC patients than from controls was found. No relationship was observed between cytokine production and cancer stage. The regression analysis evidenced a significant correlation between IL-lbeta and IL-6 monocyte-release in HNSC patients and in controls, so suggesting a possible autocrine control of IL-6 production by other cytokines.