A Prospective Study of Humoral and Cellular Immune Responses to Hepatitis B Vaccination in Habitual Marijuana Smokers

Exposure to δ9-tetrahydrocannabinol (thc) in vitro and in animal models can significantly impair the differentiation, activation and function of dendritic cells, t cells and b cells. however, studies directly assessing the impact of marijuana smoking on human immunity are lacking. a prospective study of immune responses to a standard hepatitis b vaccination was therefore carried out in a matched cohort of 9 marijuana smokers (ms) and 9 nonsmokers (ns). in addition to their regular marijuana use, ms smoked four marijuana cigarettes in a monitored setting on the day of each vaccination. blood samples were collected over time to assess the development of hepatitis b-specific immunity. the majority of subjects from both the ns (8) and ms (6) groups developed positive hepatitis b surface antibody titers (>10 iu/l) and of these 6 ns and 5 ms were classified as high antibody (good) responders (>100 iu/l). the development of a good response correlated with the presence of hepatitis b-specific t cell proliferation and cytokine production, resulting in a clear distinction regarding the immune status of good responders versus non-responders. however, even though there were slighter more non-responders in the ms cohort, there were no significant differences between ms and ns with respect to peripheral blood cell phenotypes or vaccination-related changes in hepatitis b responses. while a larger cohort be required to rule out a small suppressive effect, our findings do not suggest that habitual marijuana smoking exerts a major impact on the development of systemic immunity to hepatitis b vaccination.