A Study of Immunogenicity of Intensified Hepatitis B Vaccination in Children Being Treated for Acute Lymphoblastic Leukemia

Changes in the hepatitis B surface antibody in childhood acute lymphocytic leukaemia survivors after treatment with the CCLG-ALL 2008 protocol

Antibody levels after hepatitis B virus (HBV) vaccination may be affected by suppression of the immune system due to cancer therapy. As such, childhood acute lymphocytic leukaemia (ALL) survivors are at risk of HBV infection due to immunosuppression secondary to chemotherapy. However, the hepatitis B surface antibody (HBsAb)-seropositive rate of childhood ALL survivors after chemotherapy is unknown, and the need to revaccinate HBsAb-seronegative ALL survivors is not appreciated in China. To assess the changes in HBsAb before and after chemotherapy, we retrospectively analyzed clinical data from 547 patients treated with the Chinese Children Leukaemia Group (CCLG)-ALL 2008 protocol from 1 April 2008 to 30 August 2019. The results revealed that 416 patients (76·1%) were HBsAb-seropositive at diagnosis, and at the time of the cessation of chemotherapy, 177 patients (32·4%) were HBsAb-seropositive and 370 patients (67·6%) were HBsAb-seronegative. Interestingly, 11 patients who were HBsAb-seronegative at diagnosis converted to seropositive at the time of the cessation of chemotherapy. HBsAb titres were decreased after chemotherapy (P < 0·0001). Further, patients with higher HBsAb titres at diagnosis were more likely to maintain protective antibody titres at the completion of chemotherapy (P < 0·0001). The loss of antibody was more remarkable in younger patients (≤ 10 years) both at diagnosis (P = 0·009) and at the completion of chemotherapy (P = 0·006). In summary, this study showed that 67·6% of patients were HBsAb-seronegative at the time of the cessation of chemotherapy, which indicates that ALL survivors are at high risk of HBV. As a result, HBV revaccination after chemotherapy should be highly valued in ALL survivors.