To identify side effects of Sofosbuvir/ Daclatasvir treatment regimen of chronic HCV GT-4 infection.

• To assess the occurrence and the prevalence of RAVs in patients with treatment failure and relapse after sofosbuvir and daclatasvir with assessment of their types .
• To examine the GT4 subtypes by phylogenetic analysis and baseline sequence variability among subtypes and their potential impact on treatment outcome and development of viral resistance in patients who received a regimen of Sofosbuvir/ Daclatasvir for treatment of chronic HCV GT-4.
• To assess the differences in patient demographics across GT4 subtypes.

Hepatitis C virus (HCV) chronically infects approximately 120-130 million individuals worldwide .Mortality related to HCV infection has been estimated at approximately 300,000 deaths per year..

Direct antiviral agents (DAAs) effectively eradicate HCV and rapidly improve residual liver functions. Current HCV eradication rates have exceeded 90% in a very short time .

Hepatitis C virus genotype 4 (GT4) is genetically diverse, with 17 confirmed subtypes, and comprises approximately 13% of infections worldwide [3]. In Egypt, GT4 accounts for approximately 90% of infections, with subtype 4a predominating .

Sofosbuvir and daclatasvir are generally well tolerated with only a few adverse effects reported.

Hepatitis C virus resistant associated variants (RAVs) are seen in most patients who do not achieve sustained virological response (SVR). These resistance-associated mutations depend on the class of direct-acting antiviral drugs used and also vary between hepatitis C virus genotypes and subtypes.

Donaldson et al performed an analysis on four phase III clinical trials in search of common RAVs against sofosbuvir, discovering L159F, C316N, and V321A were associated with virological failure. Interestingly, this study also verified S282R mutation as associating with failure.

NS5A RAVs can be very common, with Y93H detected in up to 15% of the population and L31M in up to 6.3%. Other RAVs tend to also be fairly common detected in approximately 0.3%-3.5% of the population

Inclusion Criteria:

• Anti HCV positive patients either chronic HCV or liver cirrhosis. • Detectable HCV RNA by quantitative polymerase chain reaction (PCR) prior to treatment

Exclusion Criteria:

• Co-infection with hepatitis B virus .
• Presence of malignancy before treatment.
• End-stage liver disease (Child score more than 9).
• Major co-morbid disease e.g heart failure

Cases will be recruited from the viral hepatitis clinic, department of tropical medicine, Alrajhi Liver hospital, Assiut University. The lab. work will be done by researchers from Medical Microbiology and Immunology department, Faculty of Medicine, Assiut University-University of Cincinnat, USA and Clinical pathology department, Assiut University.