Antibody response to hepatitis b immunization in Egyptian children with sickle cell disease

Abstract

Background: Despite improvement in the safety of blood products, sickle cell disease (SCD) and thalassemic patients are at greater risk than the general population for hepatitis B infection and chronic liver disease, making hepatitis B immunization especially important for this population. This study was conducted to evaluate and follow up the antibody response to hepatitis B vaccination, in patients with SCD, after 1-15 years of vaccination. Methods: participants were 30 SCD and 30 thalassemic patients attending the Hematology Department, Children’s Hospital, Cairo University as well as 30 ages and sex matched normal controls. They were subjected to clinical evaluation, complete blood count, and measurement of liver transaminases, serum bilirubin, and serum ferritin levels as well as estimation of anti-HBs titer by enzymatic immunoassay. Results: Anti-HBs titers in SCD patients ranged between 5.6 and 381 IU/L (54.83 ± 15.30), while the levels of thalassemic patients ranged between 16 and 343 IU/L (93.4 ± 30) and those of the control group ranged from 10 to 523 IU/L (83.4 ± 28.1) which revealed statistically significant decrease in SCD patients compared to thalassemic and healthy controls (p =0.0317). Out of the 30 SCD patients, 40% showed anti-HBs titer below 10 IU/L (non-protective titer), while none of the thalassemic patients or the control group revealed the same. Achievement of a protective titer had no correlation with sex, consanguinity, or any of the clinical or laboratory data tested. Conclusion: Immune dysfunction in thalassemia is not playing a major role in response to hepatitis B vaccination. However, SCD children should have their anti-HBs titer measured after routine hepatitis B immunization to ensure that they achieved protective titer, then after 1 year of vaccination and repeated every 5 years and those who do not seroconvert should receive additional doses. Booster HBV vaccination of unprotected SCD patients seems mandatory.

Keywords: sickle cell, immunity, hepatitis B, immunization

Egypt J Pediatr Allergy Immunol 2010;8(2):67-73