Analysis of major histocompatibility complex and CTLA-4 alleles in Brazilian patients with primary biliary cirrhosis.

BACKGROUND AND AIMS

Predisposition to primary biliary cirrhosis (PBC) has been classically linked to HLA-DRB1 locus. However, the presence of the HLA-DRB108 antigen has been reported in less than one-third of PBC patients from Northern Europe and Japan. Recently, polymorphisms in the tumor necrosis factor alpha (TNFA) gene promoter at position -308 and in exon 1 of the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene at position 49 have been associated with susceptibility to PBC in Caucasians. In addition, the presence of HLA-DRB108 and the TNFA*1 allele was also linked to progression to end-stage liver disease. The aims of the present study were to investigate the frequencies of HLA-DR and DQ antigens and TNFA and CTLA-4 alleles in PBC patients from a different genetic background, as well as to assess the role of TNFA alleles and HLA-DR antigens in disease progression.

METHODS

Determination of HLA-DRB1, DQB1, TNFA and CTLA-4 alleles was performed in patients with PBC and healthy controls using polymerase chain reaction-based techniques.

RESULTS

Frequencies of HLA-DR and DQ antigens were similar in PBC patients and healthy controls. Accordingly, no association between TNFA and CTLA-4 alleles was observed in PBC patients. The histological stage at admission of patients with PBC also showed no correlation with HLA antigens and TNFA and CTLA-4 alleles.

CONCLUSIONS

Susceptibility to PBC in Brazil is not associated with HLA-DR and DQ antigens and CTLA-4 genotypes. TNFA alleles were not shown to influence disease progression.