Chronic hepatitis C virus infection: Is there a correlation between HCV genotypes and the level of viremia?

A molecular chaperone glucose-regulated protein 94 blocks apoptosis induced by virus infection

The hepatitis C virus (HCV) E2 protein has been shown to block apoptosis and has been suggested to facilitate persistent infection of the virus. Here, we report that the anti-apoptotic activity of E2 is mediated by activation of nuclear factor kappa B (NF-kappaB) that directs expression of survival gene products such as tumor necrosis factor (TNF-alpha) receptor-associated factor 2 (TRAF2), X-chromosome-linked inhibitor of apoptosis protein (XIAP), FLICE-like inhibitory protein (FLIP), and survivin. Increased levels of these proteins were observed in HCV-infected cells and a cell line producing HCV E2 protein. The activation of NF-kappaB was mediated by HCV-E2-induced expression of the molecular chaperone glucose-regulated protein 94 (GRP94). Overexpression of GRP94 alone resulted in expression of anti-apoptotic proteins and blocked apoptosis induced by tumor-necrosis-related apoptosis-inducing ligand (TRAIL). Interestingly, increased levels of GRP94 were observed in cells supporting HCV proliferation that originated from liver tissues from HCV patients. Moreover, small interfering RNA (siRNA) knock-down of GRP94 nullified the anti-apoptotic activity of HCV E2.

CONCLUSION

These data indicate that HCV E2 blocks apoptosis induced by HCV infection and the host immune system through overproduction of GRP94, and that HCV E2 plays an important role in persistent HCV infection.

Hepatitis C in dialysis units: the Saudi experience

Hepatitis C virus (HCV) infection is a significant health problem, as it can lead to chronic active hepatitis, liver cirrhosis, and hepatic carcinoma. Patients undergoing hemodialysis treatment are at increased risk of contracting HCV and other viral infections. This is primarily due to their impaired cellular immunity, underlying diseases, and blood exposure for a prolonged period. Transmission of viral hepatitis, and in particular HCV in dialysis units, has been showing a progressive increase worldwide, ranging between 5% in some western countries and up to 70% in some developing countries. The annual rate of HCV seroconversion in Saudi Arabia is 7% to 9%, while its prevalence is variable between 15% and 80%. This prevalence remained at almost 50% in recent years, despite the further increase in number of patients with end-stage renal disease and the expansion of dialysis services. The most prevalent genotypes in Saudi Arabia are genotype 4 followed by genotypes 1a and 1b, whereas genotypes 2a/2b, 3, 5, and 6 are rare. Genotypes 1 and 4 were associated with different histological grades of liver disease. Mixed infections with more than one genotype were observed in some studies. Isolation of dialysis machines and infected patients, together with strict application of infection-control policies and procedures and continuous education and training of nursing staff, remain the cornerstone in prevention and control of the spread of HCV infection in dialysis units. Interferon (INF)-alpha or pegylated INF, alone or in combination with ribavirin, have shown great promise in the treatment of chronic HCV in dialysis patients.