A novel virus designated TT virus (TN) has been reported to be involved In the development of posttransfusion non-A-E hepatitis. This work was conducted to Investigate the presence of this virus and clarify its possible relation to liver dysfunction in polytransfused children. 40 children with repeated blood and/or blood products transfusion due to thalassemia (n=17), leukemia (n=9), hemophilia (n=9), and aplastic anemia (n=5), and 10 healthy children were studied. They were subjected to detailed history taking, full clinical examination, abdominal ultrasonography, and laboratory investigations for liver function, hepatitis B virus (HBsAg) and hepatitis C virus (HCV antibody) by ELISA, Detection of TN DNA was carried by PCR using two primers from conserved region of the viral genome (T601/T935). TTV DNA was detected in 26 cases (65%) of the patient and one (10%) of the controls. HCV-Abs was detected In 55% (22 cases) of the patient and 16 (61.6%) of the TTV positive cases. A significant difference in serum alanlne aminotransferase (ALT) and aspartate aminotransferase (AST) levels was found among TTV-HCV colnfection group In comparison with other groups while no significant difference was detected between TN positive group and other groups. In conclusion TT viremia is frequently encountered among children with repeated blood transfusion. Its transmission is probably through transfusion of blood or its components, and although it does not appear to cause liver disease by Itself the possibility remains that TTV may aggravate liver disease caused by HCV |