Interleukin 2 receptor expression in patients with head and neck squamous carcinoma. Effects of thymosin alpha 1 in vitro

Altered cellular immunity in patients with advanced head and neck cancer includes impairments in lymphokine production, blastogenesis, in vitro cytotoxicity, and T-cell levels. Recent evidence for the potential importance of in lymphokine interleukin 2 (IL-2) in patients with cancer prompted a study of the kinetics of IL-2 receptor expression on lymphocytes from patients with untreated advanced head and neck cancer and normal subjects and an evaluation of the in vitro effects of the T-cell immune-reconstituting peptide, thymosin alpha 1. Concanavalin A-stimulated IL-2 receptor expression was maximal after 72 hours and was higher in normal subjects than in patients. This was due to lower levels of helper/inducer (CD4) cells expressing IL-2 receptors in the patients compared with the normal subjects. Thymosin alpha 1 further decreased levels of IL-2 receptor-positive (both CD4 and CD8) cells at 48 and at 72 hours. At 96 hours, levels of IL-2 receptor-positive cells and proportions of cells in G2 and M phases of the cell cycle were similar among both groups of subjects. Simultaneous cell kinetic studies indicated that thymosin alpha 1 down regulation of IL-2 receptors was not due to an effect on proliferation and that differences in IL-2 receptor expression at 72 hours among normal subjects and the patients with cancer were more likely related to differences in cell proliferation kinetics.