Effect of oral alcohol administration on plasma cytokine concentrations in heavy drinking individuals

Alcohol is known to modulate the immune system, including cytokines, under conditions of both acute consumption and chronic use. The specific pro- and anti-inflammatory effects and mechanisms whereby alcohol consumption modulates circulating cytokine concentrations are not well understood. Few studies in humans have investigated the effect of acute alcohol consumption on plasma cytokine concentrations in individuals who are heavy drinkers.

Data were pooled from two studies involving a total of 25 non-treatment seeking, heavy drinking individuals who undertook an oral alcohol administration procedure. Plasma cytokine [Interleukin-10 (IL-10), Interleukin-6 (IL-6), Interleukin-18 (IL-18) and Tumor Necrosis Factor-alpha (TNF-α)] concentrations were measured at two baseline timepoints, then three hours after alcohol administration, and finally when breath alcohol concentrations returned to zero. Linear mixed models were conducted to determine whether there was a significant effect of time on cytokine concentrations.

There was a significant reduction in TNF-α concentration (F [3, 20.42] = 4.96, p = 0.01, η²_p = 0.42) post alcohol administration, compared to baseline concentrations, and a significant increase in IL-6 concentrations (F [3, 27.81] = 9.06, p < 0.001, η²_p = 0.49) post alcohol administration, compared to baseline. There were no significant changes in IL-18 or IL-10 concentrations.

To our knowledge, this is the first study to examine the acute effect of oral alcohol consumption on peripheral inflammatory markers in individuals with alcohol use disorder. Results indicate a clinically relevant increase in proinflammatory cytokines approximately 3 h after initial alcohol ingestion. Further research should be done to elucidate the complex interaction between alcohol and the immune system.