Clinical significance of TT virus in chronic hepatitis C

Clinical outcomes of Torque teno virus-infected thalassemic patients with and without hepatitis C virus infection

Background

Although a marked proportion of thalassemic patients acquire Torque teno virus (TTV) through blood transfusion, its clinical importance is unclear. This study was designed to investigate the clinical importance of TTV infection in thalassemic patients with and without hepatitis C virus (HCV) co-infection in Iran.

Methods

In this case-control study, 107 thalassemic patients on chronic transfusion and 107 healthy individuals were selected. According to HCV and TTV infection status (detected by semi-nested PCR), patients were categorized into 4 groups: TTV and HCV negative, TTV positive, HCV positive, and TTV and HCV positive. Blood ferritin, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels in these 4 groups were assessed.

Results

Approximately half of the thalassemic patients (50.5%) and 27.1% of controls had TTV infection. Thalassemic patients had a greater chance of TTV infection compared to the control group with a sex-adjusted OR of 4.13 (95% CI=2.28-8.13). The increased levels of ALT, AST, and ferritin in the TTV and HCV-infected group were not significantly different from those in the TTV and HCV negative group. Co-infection with TTV and HCV did not significantly increase ALT, AST, and ferritin levels compared to infection with TTV alone.

Conclusion

Although common in thalassemic patients, TTV infection appears to have a negligible role in increasing the severity of liver disease, even when co-infection with HCV occurs.

Unraveling the puzzle of human anellovirus infections by comparison with avian infections with the chicken anemia virus

Current clinical studies on human annelloviruses infections are directed towards finding an associated disease. In this review we have emphasized the many similarities between human anellovirus and avian circoviruses and the cell and tissue types infected by these pathogens. We have done this in order to explore whether knowledge acquired from natural and experimental avian infections could reflect and be extrapolated to the less well-characterized human annellovirus infections. The knowledge gained from the avian system may provide suggestions for decoding the enigmatic human anellovirus infections, and finding the specific disease or diseases caused by these human anellovirus infections. Each additional parallelism between chicken anemia virus (CAV) and Torque teno virus (TTV) further strengthens this premise. As we have seen information from human infections can also be used to better understand avian infections as well. Increased attention must be focused on the "hidden" or unrecognized, seemingly asymptomatic effects of circovirus and anellovirus infections. Understanding the facilitating effect of these infections on disease progression caused by other pathogens may help to explain differences in outcome of complicated poultry and human diseases. The final course of a pathogenic infection is determined by variations in the state of health of the host before, during and after contact with a pathogen, in addition to the phenotype of the pathogen and host. The health burden of circoviridae and anellovirus infections may be underestimated, due to lack of awareness of the need to search past the predominant clinical effect of identified pathogens and look for modulation of cellular-based immunity caused by co-infecting circoviruses, and by analogy, human anneloviruses.

Clinical outcome of frequent exposure to Torque Teno virus (TTV) through blood transfusion in thalassemia patients with or without hepatitis C virus (HCV) infection

As a consequence of the high prevalence of TorqueTeno virus (TTV) in blood donors, thalassemia patients frequently acquire various genotypes of this virus through therapeutic blood transfusions. At present, the clinical consequences of TTV infection remain indeterminate for these patients. Here, several hundred thalassemia patients were tested for the presence of TTV and its genotypes using a combination of PCR and clone-based DNA sequencing. Approximately 10% (12/118) of the patients aged 2-20 years remained negative for TTV including eight genotypes of SENV. Ferritin, aspartate-aminotransferase (AST) and alanine-aminotransferase (ALT) levels were invariably lower in TTV-negative patients (P = 0.02, <0.01, and 0.06, respectively) than in TTV-positive patients. Patients with TTV-HCV co-infection showed elevated ferritin and ALT levels compared with patients with TTV infection alone (P < 0.02 and P < 0.01). AST and ALT levels were within the normal range for all TTV-negative patients, whereas abnormal levels of AST and ALT were seen in a significant proportion of TTV-positive patients (30.7% and 33.6%, respectively) and patients with TTV-HCV co-infections (70.0% and 56.6%, respectively). Only TTV-positive patients (28.0%) and patients with TTV-HCV co-infections (36.3%) had hyper-ferritin levels (> or =3,000 ng/ml). The genotype(s) of TTV responsible for the liver dysfunction could not be determined. However, high levels of AST and ALT were found to be correlated with detection of a higher number of TTV genotypes in the patients. The data suggests that frequent and persistent TTV infection through blood transfusion is associated with hepatic dysfunction and/or damage in transfusion dependent thalassemia patients.

Clinical significance of SEN-virus on interferon response in chronic hepatitis C patients

BACKGROUND AND AIM

A novel virus, SEN-virus (SENV), was recently discovered. It has been reported as a candidate for a non-A-E hepatitis virus. However, much is still unknown about the clinical significance of SENV. The aim of the present study was to clarify the clinical significance of SENV in patients coinfected with SENV and hepatitis C virus (HCV).

METHODS

The 52 subjects had chronic hepatitis C and had undergone interferon (IFN) therapy. SEN virus DNA was investigated by using polymerase chain reaction with SENV-specific primers, which we designed to detect all strains of SENV. Additionally, SENV-D and -H were detected by consensus primers.

RESULTS

Thirty-five patients were SENV-DNA positive and 22 patients were SENV-D- or -H-positive before IFN therapy. After IFN therapy, in the HCV-RNA eradication group, all cases normalized their serum alanine aminotransferase (ALT). However, in the no eradication group, the ALT no-response rate was 68.7%. In contrast, in the SENV eradication group, the ALT no-response rate was 51.9%, and in the no eradication group, it was 37.5%. Also, in the SENV-D and -H eradication group, the ALT no-response rate was 54.5%, and in the no eradication group, it was 36.4%. The changes in ALT after IFN therapy were significantly correlated with the changes in HCV RNA, but no correlation was found with the SENV DNA presence.

CONCLUSIONS

Hepatocellular injury in patients with chronic hepatitis who are coinfected with HCV and SENV appears to primarily be caused by HCV, and is less attributable to SENV.