Acute alcohol effects on cytokine concentrations in healthy young adults

Background 
A common example of exposome pressure on immune fitness is the consumption of alcohol. In a previous study we demonstrated that (sic) the morning following an evening of heavy alcohol consumption (i.e. during alcohol hangover) significant increases of cytokine concentrations of IL-6 and IL-10 were observed. The aim of this study was to examine salivary cytokine concentrations over time in the first 7 hours directly after the consumption of alcohol.
Method N = 17 healthy young adults participated in an experimental study, comprising an alcohol test day and alcohol-free control day. A saliva sample was collected at baseline, i.e. before beverage consumption (alcohol or placebo) (timepoint 1). Subsequently, they consumed alcohol on the alcohol test day (to reach a BAC level of 0.08%) or received a placebo drink on the control day. Saliva was collected hourly for 7 hours, using the passive drool method (timepoint 2 to timepoint 8). Saliva concentrations of IL1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, GM-CSF, IFN-γ and TNF-α were assessed for each timepoint. Only those cytokines that could be reliably determined on multiple timepoints (<25% under the lower limit of detection) were used for statistical analysis. Outliers (>3SD difference from group average) were removed from the dataset. To correct for day-to-day variance in cytokine concentrations, baseline-corrected data were used for the analysis: the difference score (alcohol minus control) on T1 (baseline) was subtracted from all subsequent alcohol measurements (T2 to T8). GLM for repeated measures was used to compare cytokine concentrations on the alcohol and control day across the timepoints. Differences were considered significant when P < 0.05.
Results 
For N = 15 participants the salivary cytokine concentrations of IL-1β, IL-8, TNF - α could be reliably determined. Relative to the control day, significantly increased salivary cytokine concentrations were found on the alcohol day for IL-1β on time points T2 (P = 0.038), T3 (P = 0.048), and T8 (P = 0.0001). No significant differences were found for IL-8 and TNF-α.
Conclusion 
The current findings confirm that acute alcohol consumption has a direct increasing effect on cytokine concentrations in healthy young adults. However, the observed effects are of a much smaller magnitude as those seen when alcohol is consumed in the evening and cytokine concentrations are assessed the following morning, approximately 9 hours after stopping drinking.