RESUMEN
The study evaluates the probable alteration of the immune system in multitransfused thalassaemics and the modification of their immune response following administration of hepatitis B virus (HBV) vaccine. B-thalassaemics (n = 50) and EB-thalassaemics (n = 30) who received multiple blood transfusion for the chronic anaemic status had significant iron overload. They had high prevalence for hepatitis B carrier state and almost all were exposed to hepatitis B virus during the course of transfusion as shown by the positivity of hepatitis B virus markers. Thalassaemics in presence of iron overload have altered immune status in terms of depressed T-lymphocytes and raised immunoglobulins G and M. However, they showed 100 per cent seroconversion with production of antibody to hepatitis B surface antigen following Hepatitis B vaccination.