Increased interleukin-12 serum levels in chronic alcoholism

Background/Aims: In the present study the serum levels of interleukin-12 were analyzed in alcoholic patients in order to explore the possible relationship between them and both the ethanol intake status and the existence of alcoholic liver disease. Methods: For that purpose interleukin-12 levels were analyzed in a total of 26 alcoholic patients. Additionally, both interferon-gamma and interleukin-4 serum levels were measured in the same patients as a means of exploring the balance between the T-helper-1 and T-helper-2 immune responses. All patients had consumed at least 90 g of ethanol per day for more than 5 years. Fourteen were alcoholics without liver disease (AWLD group) and the other 12 patients were diagnosed as having alcoholic liver cirrhosis. In parallel to the patients, 10 age- and sex-matched heatlhy volunteers were included in the study. Results: Our results show that interleukin-12 serum levels are significantly increased in AWLD patients as compared to normal controls (p<0.05). In patients with cirrhosis, interleukin-12 serum levels varied, depending on the ethanol intake status at the time of evaluation. Accordingly, as compared to normal controls, significantly increased concentrations of serum interleukin-12 were found in the alcoholic liver cirrhosis patients with active ethanol intake (ALCET group) (p<0.01), while in the cirrhotic individuals with at least 1 year of alcohol withdrawal interleukin-12 serum levels remained within the normal range. Only the cirrhotic patients had increased interferon-gamma serum levels. Among them, the highest levels were found for individuals from the ALCET group, the differences with respect to the healthy subjects being close to statistical significance (p=0.05). No significant differences were detected regarding interleukin-4 serum levels for any of the groups of patients analyzed compared to the control individuals. Conclusions: Our results show the existence of a relationship between ethanol intake and increased interleukin-12 serum levels, suggesting that this cytokine may play an important role in the induction of the immunological abnormalities found in chronic alcoholism, independently of whether or not alcoholic liver disease is present.