Lymphocyte subpopulations and mitogenic responses in nasopharyngeal carcinoma, prior to and after radiotherapy.

Eighteen patients with nasopharyngeal carcinoma (NPC) were compared to matched controls, before or after cobalt therapy, for the ability of their peripheral blood lymphocytes to: (1) form E and EAC rosettes and (2) mount a proliferative response with PHA, Con A and ALG. A slight decrease in the percentage of E rosettes and a moderate hyporesponsiveness to PHA and Con A were observed before treatment. The statistical significance of these alterations was borderline. Within the group of treated patients a much greater depression, including the response to ALG, was found, although a few long-term survivors responded to mitogens as well as the controls. These findings stress the difficulty of interpreting the results of a longitudinal study of cell-mediated immunity, specific or non-specific, in cancer patients. Finally, by comparing the proliferative response to the three mitogens before and after radiotherapy, it is suggested that their differential effect on these responses might be used in man, as it was in mice, to delineate lymphocyte subpopulations.