Relação entre o HLA e o clareamento espontâneo do vírus da hepatite C

Abstract

Approximately 20% of Hepatitis C virus (HCV) infected individuals clear the virus [3]. The knowledge of host factors that influence the course of HCV infection is still limited. Factors such as ethnicity and route of infection make even more difficult to understand which host-dependent genetic factors influence the hepatitis C outcome. Aims: To investigate whether HLA alleles are associated with clearance of HCV infection in a highly admixed Brazilian population. Methods: HLA-A, -B, -Cw, -DRB1 and DQB1 genotyping were performed in a Brazilian cohort of 135 HCV infected subjects among which 45 cleared HCV infection (cases) and 90 had persistent viral infection (controls). Controls were matched by sex, ethnicity (withes and non whites) and expected route of infection (high infectious dose or low infectious dose). P-values were corrected for multiple comparisons using Bonferroni s correction. Results: We didn t identify any significant association between HLA alleles and the outcome of HCV infection of all ethnic population. However, a new protective association of HLA-DQB1*04 (p= 0,006; pc= 0,030) and a rarely described protective association of HLA-DRB1*08 (p= 0,004; pc= 0,048) were found only among whites, but not among non whites patients. The DRB1*11 allele, previously reported in homogeneous population, was associated with HCV clearance (p= 0,020) only among patients with expected high-dose exposure. Conclusion: We conclude that the immunogenetic basis for HCV clearance differs between ethnic groups and route of infection. Even in an ethnically complex population it is important to establish an ethnic classification to match patients and homogenize groups and to allow stratified analysis to identify different associations for each ethnicity.