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Background: TTV is the first human circoviridae that was isolated from Japanese patients with unknown hepatitis in 1997. Since then, several studies have been done on different aspects of TTV pathogenesis. The aim of this study is to determine the prevalence of TTV in patients with chronic hepatitis using two different primer sets. Materials and Methods: In this descriptive study, blood samples from 240 patients with chronic hepatitis C at Professor Alborzi Clinical Microbiology Research Center were assessed in terms of the presence of TTV DNA in plasma through the nested polymerase chain reaction using two primer sets. Results: Of the 240 patients, TTV-DNA was detected in 220 (92%) patients with chronic hepatitis C using 5΄-UTR primer and in 12 (5%) patients using N22 primer. According to the demographic data, there was not a significant difference between male female patients in prevalence of TTV infection. Conclusion: The prevalence of TTV DNA in plasma samples from patients with chronic HCV by using 5΄-UTR primer was high and it was congruent with studies done in other countries however, N22 primer showed a lower prevalence of viral DNA in the samples. Overall, there was not a significant correlation between sex and the presence of viral DNA in patients. Controversial or high prevalence of this virus in HCV infected people necessitate further studies for determining the relationship between HCV and TTV infection.

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Background: Chronic hepatitis B virus (HBV) infection is a multi-factorial disease that is accompanied with serious clinical complications. Host’s genetic background, especially immune–genetic factors, is critical in the pathogenesis of infection. Gamma interferon ((INF-γ) and its receptor have an important role in immune response to the virus and clinical course of the disease. The aim of this study is to investigate the association between single nucleotide polymorphism -611G/A located in promoter of gamma interferon receptor1 gene (INFGR1) and chronic HBV infection. Materials and Methods: In this Case Control study, genomic DNA from peripheral blood samples of 150 chronically HBV infected patients and 150 healthy controls was extracted by phenol-chloroform method. DNA analysis was performed by PCR-RFLP method and P<0.05 was considered significant. Results: After stages of genotyping and statistical analysis, a significant difference was observed between patient and control group, so that genotype GG was higher in the control group compared to the patient group. Conclusion: The host’s immune-genetic background can play an important role in the pathogenesis of infectious disease. Variations in INFGR1 were related to several diseases. The results showed that the presence of GG allele is accompanied by a decrease in susceptibility to chronic HBV infection.

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Background: Hepatitis B virus (HBV) is a member of hepadenaviridae family, which is infectious for humans and a few animal species. Successful clearance and elimination of infection from the body or development of HBV infection to chronic disease depend on the host genetic background in immune system genes. Interleukin-12 (IL12) and also Interleukin-12 Receptor B1 (IL 12 RB1) are the key factors in the spontaneous clearance of viral infections, especially HBV. The aim of the present research is to investigate the association between Interleukin-12 receptor B1 gene polymorphism (rs11575934 A/G) and susceptibility to chronic Hepatitis B virus infection.

Materials and Methods: In this case-control study, genomic DNA of 150 chronic HBV infected patients and 150 healthy controls were extracted from peripheral blood cells. Single nucleotide polymorphism (rs11575934 A/G) was genotyped using polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP).

Results: The frequency of GG, AG, AA genotypes was 6.7%, 40.7%, and 52.7% in chronic patients and 12.7%, 41.3%, and 46% in control group, respectively. No statistically significant difference between case and control groups has been observed (p=0.176).

Conclusion: In the present study, no significant correlation between rs11575934 A/G single nucleotide polymorphism of the IL12RB1 gene and susceptibility to chronic hepatitis B virus infection has been observed. According to the study, this polymorphism does not affect the susceptibility to chronic HBV infection.