Promoter region polymorphism & expression profile of toll like receptor-3 (TLR-3) gene in chronic hepatitis C virus (HCV) patients from India.

BACKGROUND & OBJECTIVES: Hepatitis C virus (HCV) induces an immune response of the host, manifested by the formation of anti-HCV antibodies mediated by adaptive and innate immunity. Toll-like receptors (TLRs) play a pivotal role in innate immunity system. This study was aimed to investigate the promoter region polymorphism and expression of TLR3 gene in patients with chronic HCV infection. METHODS: Patients with chronic HCV infection (N=180) and an equal number of age-sex matched controls were included in the study. Patients positive for HCV-RNA were subjected to analysis of TLR3 polymorphism by direct sequencing of PCR products verified by comparing with the sequences reported in the National Centre for Biotechnology Information (NCBI) database (accession number: NT 022792). Expression of TLR3 gene was analyzed by semiquantitative RT-PCR using housekeeping ß-actin gene as the internal control. RESULTS: Polymorphisms at position -288G/A and -705A/G were identified. The results were significant in -705 allele (P=0.004) OR 2.79(1.46-5.42) and were associated with high risk of HCV infection. In silico sequence analysis showed the presence of ectropic viral integration site 1 encoded factor, in which G at -705 results in the loss of this site. The -7C/A polymorphism was not seen in our study cohort. The expression of TLR3 was upregulated in chronic HCV patients compared to healthy controls. INTERPRETATION & CONCLUSIONS: Polymorphism in the -705A/G allele at the promoter region of the TLR3 gene may predispose individual to HCV infection. However association of TLR3 expression with polymorphism of TLR3 promoter was not found.

Diagnostic utility of hepatitis C virus core antigen in hemodialysis patients.

BACKGROUND: Patients undergoing hemodialysis are at high risk for Hepatitis C virus infection. Anti-HCV antibody detection is widely used for screening this infection but is not sensitive for window period detection. An ELISA to detect the HCV Core Antigen has recently become available. OBJECTIVES: To investigate the utility of the HCV core Antigen ELISA in the detection of HCV infection in hemodialysis patients and to compare with 3rd generation ELISA validated by real-time PCR. METHODS: Two hundred fifty hemodialysis patients were included in the study. Anti-HCV antibodies and Total HCVcAg was determined by third generation ELISA kits. HCV RNA was determined using Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and sensitivity of the two assays was confirmed by estimating viral load using real-time PCR. RESULTS: Forty-three out of 250 (17.2%) patients were positive for anti-HCV antibodies and HCVcAg. 13/250 (5.2%) were positive for HCVcAg but anti-HCV negative, which is statistically significant (P<0.05). All 13 were confirmed viremic by in-house nested RT-PCR leading to specificity of 100%. Viral load of 49,258+/-28,682 copies/mL were detected in HCVcAg positive cases in comparison to 239,383+/-107,805 copies/mL in the only anti-HCV positive group (P<0.001). False negative cases for HCVcAg assay accounted for 2/250 (0.8%) in which the viral load was 306+/-461 copies/mL which was significantly lower in comparison to HCVcAg positive group (P<0.001, t-test=9.982). CONCLUSIONS: Total HCVcAg ELISA is an accurate serological marker for early identification of HCV infection, than is possible by currently used serological assay. It will be useful for patients undergoing hemodialysis who have a longer window period due to immunosuppressed state. It is both a cost-effective and a less labor-intensive alternative to PCR, enhancing its clinical utility.

Promoter region polymorphism & expression profile of toll like receptor-3 (TLR-3) gene in chronic hepatitis C virus (HCV) patients from India.

Background & objectives: Hepatitis C virus (HCV) induces an immune response of the host, manifested by the formation of anti-HCV antibodies mediated by adaptive and innate immunity. Toll-like receptors (TLRs) play a pivotal role in innate immunity system. This study was aimed to investigate the promoter region polymorphism and expression of TLR3 gene in patients with chronic HCV infection. Methods: Patients with chronic HCV infection (N=180) and an equal number of age-sex matched controls were included in the study. Patients positive for HCV-RNA were subjected to analysis of TLR3 polymorphism by direct sequencing of PCR products verified by comparing with the sequences reported in the National Centre for Biotechnology Information (NCBI) database (accession number: NT 022792). Expression of TLR3 gene was analyzed by semiquantitative RT-PCR using housekeeping β-actin gene as the internal control. Results: Polymorphisms at position -288G/A and -705A/G were identified. The results were significant in -705 allele (P=0.004) OR 2.79(1.46-5.42) and were associated with high risk of HCV infection. In silico sequence analysis showed the presence of ectropic viral integration site 1 encoded factor, in which G at -705 results in the loss of this site. The -7C/A polymorphism was not seen in our study cohort. The expression of TLR3 was upregulated in chronic HCV patients compared to healthy controls. Interpretation & conclusions: Polymorphism in the -705A/G allele at the promoter region of the TLR3 gene may predispose individual to HCV infection. However association of TLR3 expression with polymorphism of TLR3 promoter was not found.