en Internal Medicine Internal Medicine Original Research: Clinical Science Original Research: Clinical Science Hepatitis C virus (HCV) infection is highly prevalent in thalassemic patients, and this may decrease the serum antibody response to hepatitis B virus (HBV) vaccine. There is also some alteration of the immune system in multi-transfused thalassemic patients, as a consequence of iron overload. We investigated whether HCY infection may reduce the effectiveness of HBY vaccine in multi - transfused thalassemic patients. Subjects were cited and studied prospectively in three groups: group I: 125 multi-transfused thalassemic patients with negative serum HCY antibody group 2: 96 multi-transfused thalassemic patients with positive serum HCV antibody (ELISA II), in at least 2 different occasions group 3: 100 healthy subjects. Matching was performed between three groups in sex, age and body mass index and subjects in all groups had negative serum HBsAg, anti-HBc and anti-HBs and received three 20 flgr/dose injections of recombinant HBV vaccine (Heberbiovac HB) in months 0, 1, 6. Anti-HBs titer was obtained one month after the last dose of vaccine and it was considered seroprotective if it was 2: 10 lUlL. Seroprotection rate was 83.2% in group 1 and 80.2% in group 2 (p=0.74) and was 86% in healthy subjects, which didn't significantly differ with HCV positive and negative thalassemics (p>0.05). Moreover, the mean values of ALT among the responders and non-responder thalassemic patients were 55.5 ± 4 l .9 and 57.4 ± 48.5 U/L respectively(p=0.802). During vaccination periods, patients in all 3 groups did not show any significant adverse reactions. Our study shows that three standard doses of HBV vaccine are immunogenic and safe in multi-transfused thalassemic patients with or without HCV infection. Hepatitis B, Hepatitis C, Thalassemia, Hepatitis B vaccine. anti-HBs, seroprotection 211 217 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-49&slc_lang=en&sid=1 H FOROUTAN 20031947532846003397 20031947532846003397 Yes From the Department of1nternal Medicine.Imom Hospital. Tehran University of Medical Sciences, H GHOFRANI 20031947532846003398 20031947532846003398 No SH . MIRMOMEN 20031947532846003399 20031947532846003399 No S KAZEMI ASL 20031947532846003400 20031947532846003400 No MJ FARAHVASH 20031947532846003401 20031947532846003401 No M NASIRI TOUSI 20031947532846003402 20031947532846003402 No