Unresponsiveness to Recombinant Hepatitis B Vaccine in Healthy Iranian Neonates: Association with HLA Antigens

Background: Hepatitis B is an important infectious disease.  Since several years ago, mass vaccination against this viral infection has become as part of routine vaccination schedule of Iran.  However, some healthy neonates, children and adults fail to generate a protective antibody response after vaccination.Objectives: To investigate distribution of HLA class-I and class-II antigens in healthy Iranian neonates vaccinated with recombinant hepatitis B vaccine. Methods: HLA-typing was performed on peripheral blood lymphocytes isolated from 25 responder and 23 nonresponder (anti-HBs < 10 IU/L) healthy neonates, using the standard microlymphocytotoxicity method. Anti-HBs antibody was quantitated by sandwich ELISA. Results: The frequency of HLA-DR7 (p<0.01), DQ2 (p<0.02) and DR13 (p<0.05) was significantly higher in the nonresponder neonates compared to the responder group.  The DR1 and DQ3 antigens were over-represented (p<0.05) in the responder vaccinees, implying positive association with the anti-HBs antibody response. Statistical analysis revealed increased frequencies of B7-DR7-DR53-DQ2 and DR13-DR52-DQ2 haplotypes in the nonresponder neonates (p<0.05). Conclusions: We found a significant association between lack of antibody response to recombinant hepatitis B vaccine and expression of certain HLA class- II antigens in healthy Iranian neonates.