| [ Summary ] |
Being a chronic liver disease, in which autoimmune mechanisms are considered to play a role in the development and perpetuation of hepatocyte damage, autoimmune hepatitis (AIH) has been established as a clinical and pathological entitiy, distinct from chronic liver disease caused by viruses, alcohol, drugs or metabolic disorders. AIH is classified into three types, type 1,2 and 3, according to the autoantibodies detected. Type 2 AIH was characterized by predominance of young female patients and high inflammatory activity. AIH was occasionally associated with other autoimmune liver diseases and termed an 'overlap syndrome'. Inflammatory activity was also influenced by genetic background and higher in DR3-positive patients than in DR4-positive patients. The HLA allotype and alleles, mainly associated with AIH, differed in various countries. The HLA allotypes associated with AIH are DR3 and DR4 in USA and European countries, DR4 in Japan, China, Mexico and Argentina and DR13 in Brazil. The alleles for HLA DR4 alleles are DRB1*0401 in the USA and European countries, DRB1*0405 in Japan, China and Mexico and DRB1*0404 in Argentina. The differences in HLA allotypes and alleles may be one of the reasons why clinical and pathological profiles of AIH differed in various countries. |