Identification of Glyceraldehyde-3-Phosphate and Alcohol Dehydrogenases as Autoantigens in Doberman Hepatitis

An autoimmune background is suspected for Doberman hepatitis (DH). It is based on the finding of mononuclear cell infiltrates in the liver, strong female bias, association to the homozygous risk factor dog leucocyte antigen (DLA) allele DRB1*00601 and aberrant major histocompatibility complex (MHC) class II expression on hepatocytes that correlates with the degree of inflammation in the liver. The aim of this study was to search for autoantibodies against liver-related antigens associated with DH. Twenty-five Dobermans with subclinical DH (SDH), 13 that clinically manifest DH (CDH) and 17 healthy controls were studied. Immunoblotting analysis detected specific antibodies in the DH sera. By mass spectrometry the targets were identified as liver-related enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and alcohol dehydrogenase (ADH). Using ELISA, anti-GAPDH IgG was detected in 36% (9/25) of SDH dogs and 69.2% (9/13) of the CDH dogs compared to healthy controls (0/17) (P < 0.0005). Anti-ADH IgG was detected in 72% (18/25) of SDH dogs and 76.9% (10/13) of CDH dogs and only in one (1/17) control (P < 0.0005). The finding of novel autoantigens, GAPDH and ADH strengthen the hypothesis that DH is an autoimmune disease of the liver. These findings suggest that DH could be diagnosed by screening for autoantibodies against the defined antigens.