Autoimmune Hepatitis in Brazil: An Overview

Autoimmune hepatitis is an immune cell‐mediated chronic liver disease of unknown cause that leads, when untreated, to cirrhosis and liver failure. Importantly, this disease affects not only adults but children as well. Genetic susceptibility is clearly important and the major susceptibility factor identified up to now is the HLA‐DRB1 locus, but other genes may play a role as well. HLA‐DRB1 alleles present in South American patients differ from those found in patients in other parts of the world. In addition, we have recently identified two chromosomal regions where additional susceptibility factors may be found in Brazilian patients, namely, the class III MHC region and the 5q31 region where the IL‐4 and IL‐13 genes are located. This review discusses the current knowledge of the pathogenesis of this autoimmune disease occurring in the setting of an immune‐privileged organ, the liver, and compares the data on gene polymorphisms studied in Brazil and in other parts of the world.