CCR5 and hemoglobin measurement: Given the importance of cell response in HBV infection, including a finding that the production of a non-functional CCR5 (Δ32 CCR5) increases the likelihood of recovery from HB in humans [11,12,33], and given the increased T-cell response to various antigens observed in animal models [31], we conducted the first study on the human population and hypothesized that both homozygous Δ32/Δ32 of CCR5 gene and homozygous AA of CCR2 gene might be bio-markers for immunological response in subjects after a HBV vaccination.