Loss of protective anti-HBs titers and seroconversion to hepatitis B vaccination in children during chemotherapy for acute lymphoblastic leukemia

BackgroundThis study aimed to evaluate loss of protective anti-hepatitis B (HBs) titers and seroconversion to hepatitis B vaccine (HBV) during chemotherapy in children with acute lymphoblastic leukemia (ALL). MethodsAnti-HBs titers were done at diagnosis. Patients were divided into two groups. Group I (protective titers >10 mIU/ml) received single double dose of HBV as booster. Titers were repeated at three time points: end of phase 1b, beginning of re-induction, and start of maintenance chemotherapy. Group II (nonprotective titers <10 mIU/L) received hepatitis B immunoglobulin (HBIG), prior to start of chemotherapy, followed by three double doses of HBV as booster. Titers were repeated at two time points: prior to first dose, and 4 weeks after third dose of vaccine. ResultsTotal 125 patients were included: 88 in group I; 37 in group II. Among group I patients, 98.7%, 90%, and 84% retained protective titers at the three points, respectively. Subgroup analysis showed that those with initial titers greater than 100 mIU/L retained protective titers better than those with titers between 11 and 100 mIU/L (p = .0001). Among group II patients, 62% and 64% attained protective titers at the two points, respectively. ConclusionsHBV boosters helped maintain protective titers during intensive ALL chemotherapy in immunized children having titers more than 10 mIU/L, and more so if titer was more than 100 mIU/L. Therefore, we propose that cut off for protective anti-HBs titers be changed to greater than or equal to 100 mIU/L. Titers between 11 and 100 mIU/L may require combined active and passive immunization. Around one-third of group II patients who fail to attain protective titers may need frequent doses of HBIG.

Automated summary

This study evaluated the loss of protective anti-hepatitis B (HBs) titers and seroconversion to hepatitis B vaccine (HBV) in children with acute lymphoblastic leukemia (ALL) during chemotherapy. The results showed that HBV boosters helped maintain protective titers in immunized children, especially if their titers were more than 100 mIU/L. For titers between 11 and 100 mIU/L, combined active and passive immunization may be required. Patients who fail to attain protective titers may need frequent doses of HBIG.