T-cell receptor polymorphism in primary biliary cirrhosis.

T-cell receptor (TCR) plays a key role in immune regulation and polymorphisms of its genes have been found in association with several autoimmune diseases. No data are available for primary biliary cirrhosis, an autoimmune liver disease the natural history of which is highly variable. We studied a TCR constant beta-2 chain polymorphism in 70 patients affected by primary biliary cirrhosis and in 70 healthy controls. The DNA chains of patients and controls were amplified by means of polymerase chain reaction using primers designed around a Bgl II polymorphic restriction site and digested for restriction fragment length polymorphism analysis. We found a slight increase of the heterozygous genotype in patients compared with controls (49 vs 40%), which became higher if only patients with early disease were considered (60 vs 40%). Heterozygous patients had less severe disease as indicated by a lower Mayo score (5.1 +/- 1.2 vs 5.7 +/- 1.2 in non-heterozygous). Our data suggest that TCR constant beta-2 polymorphism does not play a key role in modulating the multifactorial etiopathogenesis of primary biliary cirrhosis.