Type 1 and type 2 autoimmune hepatitis in adults share the same clinical phenotype

Autoimmune hepatitis (AIH) is historically classified into type 1 and type 2 on the basis of the autoantibody profile, anti-nuclear and/or anti-smooth muscle antibodies being the serological markers of type 1 AIH, whereas anti-liver/kidney microsomal antibody type 1 and/or anti-liver cytosol antibody type 1 characterise type 2 AIH.

To evaluate whether such a distinction is justified on the basis of different expression of the disease in adults.

Twenty-six adult patients with type 2 AIH and 52 age- and sex-matched patients with type 1 AIH, representative of the entire cohort of adults with type 1 AIH, were compared at onset and during follow-up.

At diagnosis, median age was 26 years (range 17-53), female sex 86%, acute presentation 43%, severe liver histology 54%, cirrhosis 14%, complete response to treatment 52%, progression of the disease 17%, and median disease duration 72 months (range 12-280). HLA-DRB1*0301 was present in 26%, HLA-DRB1*0401 in 23% and HLA-DRB1*0701 in 25%. Clinical presentation, biochemical parameters, severe liver histology, genetic profile, response rate and progression of the disease were identical between type 1 and type 2 AIH.

There is not enough clinical, biochemical, histological or genetic reason to subdivide adults with autoimmune hepatitis into type 1 and type 2 on the basis of the autoantibody profile, and the term 'autoimmune hepatitis' without qualification should be preferred.