HLA-DQ associations in type 1 autoimmune hepatitis.

OBJECTIVE

To determine whether, in patients with type 1 autoimmune hepatitis and human leukocyte antigen (HLA) DR3 and DR4 positivity, any DQ antigen is disease-specific.

MATERIAL AND METHODS

HLA class II typing was performed by restriction fragment length polymorphism in 103 patients with type 1 autoimmune hepatitis, 104 patients with chronic viral hepatitis, and 80 normal subjects. A shared association with a disease-specific DQ antigen was sought in patients with HLA-DR3, DR4, and DR3-DR4.

RESULTS

Patients with HLA-DR3 and DR4 shared positivity for DQ2, DQ4, DQ5, DQ6, and DQ7, but the associations reflected established linkages or were of low frequency. Patients heterozygous for DR3-DR4 or homozygous for either DR3 or DR4 did not have a shared DQ antigen. Only the DR3-DQ2 haplotype distinguished patients with autoimmune hepatitis from normal subjects or those with chronic viral hepatitis.

CONCLUSION

The DR3 and DR4 antigens are not associated with a single disease-specific DQ antigen in type 1 autoimmune hepatitis. The DR3-DQ2 haplotype is the principal risk factor for the disease at our referral center. Analyses by restriction fragment length polymorphism do not implicate a single susceptibility gene at the DQ locus.