HCV Flashcards
What is the family and genus of HCV?
How many genotypes are there?
Flaviviridae family and hepacivirus genus
6 main genotypes but up to 8 GTs (further divided into subtypes a/b/c…)
What are the main proteins of HCV?
Which have most sequence variability?
Structural proteins = core and envelope glycoproteins
Non-structural proteins = NS2, NS3, NS4A, NS4B, NS5A, NS5B
Most variability in env 2
What proteins do NS3, NS5A and NS5B code for?
NS3 = serine protease/RNA helicase
NS5A = Phosphoprotein used for assembly
NS5B = RdRp
How long does RNA and anti-HCV take to become detectable in HCV infection?
RNA = 1-3 weeks post infection
ALT rise = 8-10 weeks
anti-HCV = 12 weeks
How does HCV exist in a patient?
What impact does this have on sequencing and RAS?
HCV exists as a quasispecies
This means that using Sanger sequencing only population sequencing is obtained, there can be RAS which are only in minority species which may or may not be detected
How many people are estimated to have HCV worldwide?
> 70 million
What are the possible outcomes of HCV infection?
1) Acute infection with viral clearance
2) Chronic infection which can lead to necro-inflammation > extensive fibrosis > cirrhosis > HCC
What are risk factors for HCV acquisition?
IVDU
Blood products pre 1990
MSM (sexaul tranmission via heterosexual sex is rare)
Prisoners
Homelessness
Born in a high risk country
What is the relevance of IL28B in HCV infection?
Patients with an IL28B genotype are more likely to clear the infection spontaneously and with IFN and ribavirin treatment
What HCV genotype is most prevalent worldwide? Which is most common in the UK?
Genotype 1
Genotype 1 and 3 are most prevalent in UK
What is the rate of symptomatic acute HCV infection?
What are the symptoms?
~20% have symptomatic HCV infection
Jaundice, nausea, malaise
Fulminant hepatitis is very rare
What percentage of acute HCV infection clear?
~15% clear within 24 m
~85% become chronically infected
What are extrahepatic manifestations of HCV?
Mixed cryoglobulinaemia
B cell non-Hodgkin lymphoma
Glomerulonephritis
What is the limit of quantitation recommended by EASL for HCV RNA assays?
15 IU/ml
What testing should be performed in patients with ?new HCV infection?
RNA testing at 12 and 24 weeks post risk of infection as during acute infection fluctuating viral loads occur and can be negative when tested
What are contraindications to DAA treatment in HCV?
Limited life expectancy
Treatment with cytochrome P450/P-gp inducers
Age <3 years
What are the three goals of HCV treatment?
1) Reduce liver damage
2) Improve quality of life
3) Prevent onward transmission
What DAA is contraindicated in decompensated cirrhosis and why?
Protease inhibitors due to increased risk of toxicity in Child Pugh B or C
What were the SVR rates in IFN/ribavirin treatment of HCV?
40-70%
Which genotype was considered difficult to treat with:
a) IFN based regimens
b) DAAs
a) Genotype 1
b) Genotype 3
In which patient groups might ribavirin be added to a DAA regimen?
Patients with increased risk of treatment failure
1) decompensated cirrhosis
2) GT3 with compensated cirrhosis
3) Pre-DAA treatment failure with RASs
What tests are performed in patients pre-HCV treatment?
HBsAg, HBsAb, anti-HBc (vaccinate if not immune)
HIV
HAV IgG (vaccinate if not immune)
Assess liver damage with non-invasive methods (fibroscan, serum biomarkers)
Is genotyping required pre-DAA treatment?
What region is sequenced for genotyping?
No, pangenotypic regimens are available
However cheaper regimens may be available if genotype is known
5’ UTR plus core, NS5B sequencing may be required for the rarer genotypes
What are the two available pangenotypic DAA regimens? And what is the duration?
Sofosbuvir/velpatasvir - 12 weeks
Glecapravir/pibretasvir - 8 weeks
but if cirrhosis and treatment experienced then 12 weeks