Common polymorphisms in interleukin genes (IL4, IL6, IL8 and IL12) are not associated with alcoholic liver disease or alcoholism in Spanish men

Background: Preliminary data suggest that polymorphisms in cytokine genes may be involved in the genetic predisposition to alcoholic liver cirrhosis or alcohol use disorders. We thus analyze the association between these diseases and the following polymorphisms: −33T > C IL4, −174 G > C IL6, −251 T > A IL8 and 1188 A > C IL12B. Methods: 258 male alcoholics (161 without liver disease and 97 with liver cirrhosis) and 101 healthy controls were genotyped for the above mentioned polymorphisms. We examined the relationship between genotype and allele frequencies and the presence of disease, as well as the correlation with combinations of putative pro-inflammatory genotypes. Haplotypes were inferred using the expectation-maximization algorithm and haplotype frequencies were compared. Results: We found no statistically significant association between any of these polymorphisms or the combinations of pro-inflammatory polymorphisms and the risk of alcoholic liver cirrhosis or alcohol abuse or dependence. Haplotype analysis of the IL4 and IL12B polymorphisms did not show any statistical relationship either. Conclusions: Our results do not support the hypothesis that the analyzed polymorphisms confer differences in alcoholic liver cirrhosis or alcohol use disorders susceptibility.