Induction of aryl hydrocarbon hydroxylase activity in cultured human lymphocytes.

Lymphocytes from a non-cancer population (203) of non-smokers, former smokers and smokers were cultured in vitro and assayed for basal and induced AHH activity. A wide range of AHH activities was measured, but there was no indication of separate groups in the distributions of the activities or inducibility. However, smoking slightly increased the basal AHH activity and significantly decreased the inducibility. AHH activity was dependent on the age of the donor, on the season, and correlated with lymphocyte stimulation by mitogens. A lung-cancer population (49 persons) was also tested. They were all smokers, but gave results that were more like those of non-cancer non-smokers, except for the fact that 37% of them gave a basal AHH activity that was too low to be measured, compared to 16% of the non-cancer persons. The observations that many factors, such as season, age and even smoking, affect the AHH activity necessitate a careful control of conditions for the study of the association between AHH inducibility in human lymphocytes and lung cancer. As cancer itself may also have an effect such a study should be done as a prospective study of a selected population.