Hypomethylation of HLA-DPB1 as found in high compared with low vaccine responders may indeed strengthen the overall immune response as previously demonstrated by the contribution of HLA to cellular host immunity in response to anthrax vaccine adsorbed [33]; rubella vaccine [34]; hepatitis B vaccine; and the inactivated Japanese encephalitis vaccine [35]. This evidence concerns the gene HLA-DPB1 and hepatitis B virus infection.