TT virus infection in adult beta-thalassemia major patients

BACKGROUND AND OBJECTIVES: Patients with thalassemia-major are at risk of blood-borne viral infections. TT virus (TTV), a single stranded, circular DNA virus, has recently been found to be associated with acute and chronic hepatitis. The aims of this study were to assess the prevalence of TTV infection in adult patients with transfusion-dependent thalassemia, and to evaluate the clinical significance of TTV. DESIGN AND METHODS: We studied 68 adult patients with thalassemia major, 97% of whom were hepatitis C virus (HCV) antibody positive. TTV DNA was amplified from serum by heminested polymerase chain reaction (PCR). Direct sequencing of PCR products was used to establish TTV genotypes. RESULTS: TTV DNA was detected in 47 patients (69.1%). Sequence analysis of PCR products identified TTV genotype 1b as the most common viral genotype in this group. Patients co-infected by HCV and TTV had a significantly higher histologic grade score than patients with isolated HCV infection (5.1+/-2.7 vs. 2.8+/-1.7, p=0.02) while the stage score was not significantly different. INTERPRETATION AND CONCLUSIONS: TTV is highly prevalent among Italian multiply transfused patients. In these patients TTV viremia appears to affect the necro-inflammatory activity of hepatitis C, though no evidence of an effect on the evolution of fibrosis was found