Time-dependent changes in saliva cytokine concentrations during alcohol hangover: A comparison of two naturalistic studies

Purpose: A role of the immune system in the pathology of alcohol hangover has been proposed, and previous research have shown changes in serum cytokine concentrations during alcohol hangover relative to a control alcohol-free day. The current analyses compare determinations of saliva cytokine concentrations during alcohol hangover and a control day, conducted at different times after stopping alcohol consumption. Methods: Two naturalistic studies were conducted in social drinkers aged 18-35 years old. The first study (N = 36) collected saliva samples approximately 9 h after stopping alcohol consumption. The second study (N = 119) collected saliva samples approximately 13 h after stopping alcohol consumption. In both studies, saliva cytokine concentrations of IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, GM-CSF, IFN-γ and TNF-α were determined on the hangover and control day. Results: Nine hours after stopping alcohol consumption (Study 1), relative to the control day, significant increases in IL-2, IL-4, IL-5, IL-6, IL-10, IFN-γ and TNF-α concentrations were observed. In contrast, 13 h after stopping alcohol consumption (Study 2), relative to the control day, significant decreases in IL-2, IL-4, IL-5, IL-6, IL-10, GM-CSF, IFN-γ and TNF-α concentrations were observed. In both studies, changes in saliva cytokine concentrations were not significantly correlated with the amount of alcohol consumed. Whereas 13 h after stopping alcohol consumption (study 2) changes in saliva concentrations of some cytokines (i.e. levels of IL-1b, IL-2, IL-4, IL-5, and GM-CSF) were significantly negatively correlated with hangover severity. Discussion: The data suggest that the being in the alcohol hangover state is associated with changes in immune reactivity. As the direction of the changes in saliva cytokine concentrations seems time-dependent, to better understand this association, additional research is necessary, assessing immune biomarkers throughout the day