The failure of the immune system to mount a successful attack on the h
uman immunodeficiency virus (HIV) is an old enigma for AIDS research.
The high mutational capacity of HIV, which unremittingly confuses the
immune system, is a major factor in immune failure. But this alone can
not fully explain the certain and inescapable failure of the immune sy
stem, leading to full-blown AIDS. Here, we propose the hypothesis that
endogenous cannabinoids, derived mostly from macrophages, might parti
cipate in the general failure of the immune system in HIV-infected ind
ividuals.