TT-virus infection in Japanese general population and in hemodialysis patients

TT virus infection in patients on peritoneal dialysis in Taiwan

Many studies have reported the prevalence of transfusion-transmitted virus (TTV) infection in hemodialysis patients, but few reports studied the prevalence of TTV infection in peritoneal dialysis patients. In this study, we determined the prevalence of TTV in a peritoneal dialysis population in Taiwan and related its prevalence with history of blood transfusion, serum hepatitis B surface antigen (HBsAg), antibody to hepatitis C virus (anti-HCV), and serum aminotransferases (AST and ALT) levels. Serum samples from 47 peritoneal dialysis patients and a control group of 43 patients at health examination were studied for TTV viremia by using polymerase chain reaction. The rate of blood transfusion exposure (p < 0.0001), female gender (p = 0.001), younger age (p = 0.0014), and serum AST level (p = 0.012) were significantly higher in peritoneal dialysis patients. The prevalence of TTV viremia was not significantly different between peritoneal dialysis patients and the control group (23.4% vs. 37.2%). TTV infection was not associated with evident liver diseases in peritoneal dialysis patients, and the infection rate was not different between automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) patients. There was no statistically significant association between TTV infection and age, gender, transfusion history, duration of peritoneal dialysis, AST level, ALT level, HBsAg, or anti-HCV seropositivity in peritoneal dialysis patients. Our results suggest that TTV infection is not associated with evident liver diseases, and there is no difference between TTV infection in healthy individuals and peritoneal dialysis patients. TTV transmission probably occurs via routes unrelated to peritoneal dialysis.

Transfusion transmitted virus: A review on its molecular characteristics and role in medicine

The present review gives an updated overview of transfusion transmitted virus (TTV), a novel agent, in relation to its molecular characteristics, epidemiological features, modes of transmission, tissue tropism, pathogenesis, role in various diseases and its eradication from the body. TTV, a DNA virus, is a single stranded, non-enveloped, 3.8 kb long DNA virus with a small and covalently closed circular genome comprising 3852 bases. It was tentatively designated Circinoviridae virus. TTV genome sequence is heterogeneous and reveals the existence of six different genotypes and several subtypes. TTV has been reported to transmit not only via parenteral routes, but also via alternate routes. This virus has been detected in different non-human primates as well. At present, TTV is detected by polymerase chain reaction (PCR) with no other available diagnostic assays. It shows its presence globally and was detected in high percent populations of healthy persons as well as in various disease groups. Initially it was supposed to have strong association with liver disease; however, there is little evidence to show its liver tropism and contribution in causing liver diseases. It shows high prevalence in hemodialysis patients, pointing towards its significance in renal diseases. In addition, TTV is associated with several infectious and non-infectious diseases. Although its exact pathogenesis is not yet clear, TTV virus possibly resides and multiplies in bone marrow cells and peripheral blood mononuclear cells (PBMCs). Recently, attempts have been made to eradicate this virus with interferon treatment. More information is still needed to extricate various mysteries related to TTV.