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

Abstract

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.

Divergent Pro-Inflammatory Cytokine Response Induced by GB Virus C/ Hepatitis G virus (GBV-C/HGV) and Torque Teno Virus (TTV) Co-Infections in Hepatitis C Virus (HCV) Infected Thalassemia Patients

“…In the present study, prevalence of TTV and HGV co-infections with HCV infection among thalassemic subjects were found to be comparable to that reported in studies from India (Panigrahi, Saxena, Acharya & Panda, 1998;Asim, Potukuchi, Arora, Singh & Kar, 2008). Several studies based on liver enzyme profile concluded that neither HGV nor TTV has any pathogenic role in liver damage (Sampeitro et al,1997;Irshad, Joshi, Sharma & Dhar 2006;Matsumoto et al,1999). However few studies have postulated a beneficial role of HGV co-infection in the pathogenesis of HIV infections, based on study of liver enzyme profile, short term clinical observation and have included HIV/HGV co-infected patients as study subjects (Feng et al, 2014;Stapleton, Williams & Xiang, 2004).…”

Torque Teno Virus (TTV) distribution in healthy Russian population

“…TTV was first characterized as a blood-born virus and thus referred to transfusion-transmitted (TT) group of viruses [ 1 ]. Recent studies suggested the existence of other ways of transmission including parenteral [ 3 ], sexual [ 9 , 10 ], mother-to-child [ 11 , 12 ] and others [ 13 - 15 ].…”

Molecular Epidemiology of Torque Teno Virus (TTV) Isolated from in Healthy and Subjects with Chronic Hepatitis B and C in Jahrom City of Iran

“…The purpose of recent study was to survey the rate of infection of TTV in the Jahrom, Southern of Iran. TTV was first originally isolated from a patient with fulminant hepatitis in Japan in 1997 by Nishizawa and also from chronic liver disease of unknown etiology and cryptogenic hepatitis (19). These findings assumed that TTV may associate with hepatitis, although to date a causative effect has not been established (20).…”

“…These findings assumed that TTV may associate with hepatitis, although to date a causative effect has not been established (20). TTV has been found to be extremely common in humans with high worldwide prevalence, patients with a broad spectrum of hepatic disorders concomitant with HBV or HCV (19,21) as well as in healthy people that is very variable, and also in order to clear pathology of TTV infection, further studies should be performed to evaluate prevalence of TTV infection in region patients. According to the result of this study, the prevalence of TTV in patients with chronic HBV and HCV in the southern of Iran was 50.8 and 66.5%, respectively.…”