Natural history of the TT virus infection through follow-up of TTV DNA-positive multiple-transfused patients

Little is known about the natural history and the pathogenicity of the TT v irus (TTV). We present our findings of a cross-sectional study based on the TTV DNA screening of 173 multiple-transfused patients and a longitudinal s tudy based on the follow-up of TTV DNA-positive patients. Overall, 48 patie nts (27.7%) tested positive for TTV DNA. The influence of the number of blo od donor exposures on the prevalence of bloodborne viral infection indicate s that TTV, hepatitis C virus (HCV), and an RNA virus known as GB virus C/h epatitis G virus (GBV-C/HGV) share a parenteral transmission, but that TTV, in contrast to the 2 other viruses, is also transmitted by at least anothe r efficient means. The patients having a well-defined date of TTV infection were positive for TTV DNA during a mean period of 3.1 years. A chronic inf ection was observed in 31 cases (86%), TTV carriage appeared clinically ben ign in all patients. No clinical evidence of a disease potentially linked t o the TTV infection was observed in patients with TTV DNA carriage over sev eral years. The majority of TTV carriers had no biochemical evidence of liv er disease. The prevalence of elevated serum alanine aminotransferase (ALT) level was higher in the TTV DNA-positive group, even in the absence of HCV infection, but the observed peaks of ALT level were most often transient a nd very mild. The prevalence of TTV DNA observed in blood recipients is con sistent with that of TTV infection observed in blood donors. TTV infection frequently tends to persist. (C) 2000 by The American Society of Hematology .