Association of Doberman hepatitis to canine major histocompatibility complex II.

Doberman hepatitis (DH) is a chronic and progressive inflammatory liver disease that mainly affects female dogs. The high incidence of chronic hepatitis in Dobermans is suggestive of a genetic predisposition. DH is characterized by mononuclear cell infiltration and copper accumulation in the liver and major histocompatibility complex (MHC) class II antigen expression in the hepatocytes. In dogs, the MHC is referred to as the dog leukocyte antigen (DLA) system. In this study, the potential role of DLA genes in DH was investigated by sequence-based typing in the exon 2 of DLA-DRB1, -DQA1 and -DQB1. The case group comprised 37 Dobermans with subclinical or clinical DH. The control group consisted of 37 healthy Dobermans, with normal liver enzyme values and without immunosuppressive medication. The control dogs were over 10 years old to include dogs with the lowest genetic risk of DH. Our results indicate that Dobermans with homozygous DLA-DRB1*00601/DQA1*00401/DQB1*01303 [odds ratio (OR) = 14.9, confidence limit (CL) = 3.1-71.7, P < 0.00005], especially with homozygosity for DLA-DRB1*00601 (P < 0.0005), are susceptible to DH. The DQ heterodimer DLA-DQA1*00901/DQB1*00101 and the allele DLA-DRB1*01501 appear to confer protection against DH (P < 0.001). Allele and haplotype frequencies were compared using chi-squared statistics. The disease shows a complex pattern of inheritance, but the observed DLA class II association with DH suggests a role for the immune system in the development of the disease.