Cytotoxic T-lymphocyte antigen-4 A49G polymorphism is associated with susceptibility to and severity of alcoholic liver disease in Italian patients.

AIMS To determine whether the functional A49G polymorphism of cytotoxic T-lymphocyte antigen-4 (CTLA-4), a T-cell surface molecule that modulates T-lymphocyte activation and influences the risk of developing alcohol-induced autoantibodies, plays a role in susceptibility to alcoholic liver disease (ALD) and influences disease severity in Italian alcohol abusers. METHODS One hundred and eighty-three patients with chronic ALD (61 cirrhosis), 115 end-stage HCV cirrhosis, 102 non-alcoholic fatty liver disease (NAFLD), 93 healthy subjects and 43 heavy drinkers without liver disease were studied. CTLA-4 gene polymorphism was analysed by restriction analysis. RESULTS The frequency of the CTLA-4 polymorphism was higher in patients with ALD than in patients with HCV chronic hepatitis and NAFLD, healthy subjects (P < 0.0001), and heavy drinkers without liver disease (P = 0.02). In patients with ALD, homozygosity for the CTLA-4 polymorphic allele (G/G genotype) was more represented in subjects with cirrhosis (P = 0.047), and independently associated with the risk of cirrhosis (OR 3.5; P = 0.03). CONCLUSIONS The CTLA-4 polymorphic G allele, probably by interfering with the immune response, may confer susceptibility to ALD and, in homozygous state, to alcoholic cirrhosis.