The beneficial effects of taking marijuana for debilitating diseases such as multiple sclerosis remains a vigorously debated issue. Evidence for the ability of some constituents of marijuana to influence the immune system, however, does exist. In fact, it is to a nonpsychoactive component of cannabis—cannabidiol (CBD)— that some of these effects can be attributed; CBD has been reported to show anti-inflammatory properties, including the down-regulation of lymphocyte and macrophage function.
Extending these studies, Malfait et al. report that oral administration or injection of CBD significantly reduced inflammation in a mouse model of joint disease bearing a similarity to human rheumatoid arthritis. To this end, the cannabidiol appeared to evoke its anti-arthritic effects in two ways: by inhibiting T-cell responses normally induced in the arthritis model upon priming with collagen, and through a direct effect on the inflammatory pathways that lead to the eventual damage of joint tissue. Although the mechanisms by which CBD influences the immune system remain obscure, this study may open up new avenues in the search for effective treatment of chronic inflammatory disease. — SJS
Proc. Natl. Acad. Sci. U.S.A.97, 9561 (2000).