Antibody measurements
Serology tests for HBsAg, HBsAb, hepatitis B e antigen, hepatitis B e antibody, and hepatitis B core antibody were performed quantitatively using ELISA in all children before transplantation and at nearly 1 month, 3 months, 6 months and 12 months after transplantation. Blood samples were also collected to evaluate HBV serology status in donors before transplantation. HBsAb titers were defined as negative at levels <10 IU/L and positive at ≥10 IU/L; positive titers were considered to confer protective immunity against HBV.