Ethanol inhibits interferon-gamma secretion by human peripheral lymphocytes

Clinical and epidemiological evidence exists that subjects who chronically abuse alcohol are disposed to infections and certain types of cancer. In vitro inhibition of mitogen-induced lymphocyte proliferation has been shown suggesting a direct immunosuppressive effect of ethanol. Using human peripheral blood mononuclear cells we could demonstrate in vitro for the first time that even low ethanol concentrations of 6 and 12.5 mM significantly inhibit spontaneous and mitogen-induced secretion of interferon-gamma. This effect was more pronounced with lower mitogen stimulation and it increased in a dose dependent manner when higher ethanol concentrations were used. Inhibition of cell proliferation as measured by 3H-thymidine incorporation did not parallel the inhibition of interferon-gamma secretion. As this lymphokine exerts a great number of immunostimulating effects, diminished secretion might well contribute to the immune defect observed in alcoholics.