Hepatits delta Flashcards
What sort of virus is HDV?
Defective virus, requires HBsAg as helper virus to complete life cycle
Circular -ssRNA virus, smallest human RNA virus
Can replicate independently of HBV
What is the receptor for HDV (and HBV)?
Sodium taurocholate cotransporting polypeptide (NTCP)
Describe coinfection and superinfection in HDV, symptoms, likelihood of chronicity
Coinfection - occurs at same time as HBV infection:
Often leads to acute hepatitis
Can range from asymptomatic, mild disease to ALF
Usually more severe hepatitis than in HBV monoinfection
May lead to clearance of both HBV and HDV
Only results in CHD in 2%
Superinfection - infection with HDV in someone with existing HBV:
More rapid and frequent progression to cirrhosis
Usually causes severe hepatitis
Leads to CHD in 90% cases
Sometimes causes suppression of HBV
Leads to cirrhosis in 5-10 years in 80% of cases
Most severe form of chronic hepatitis
When and how would you test for HDV infection?
Anti-HDV should be performed on all new HBsAg diagnosis, should also be tested whenever clinically indicated (ie during flares or acute decompensation of liver disease)
May consider annual testing for those at high risk
HDV RNA should be tested on anyone anti-HDV pos to diagnose CHD
Anti-HDV IgM levels are related to disease activity in CHD (was used as surrogate marker of viral replication pre-PCR)
Definition of clearance of HDV
2x undetectable PCR 3-6 m apart
What are some issues with HDV quantitative assays?
WHO international standard is GT1 only
Variability in quantitation across testing labs
Variability in quantitation across genotypes
HDV Ag is not an alternative as this is not detectable in blood during chronic infection
Circular genome causes issues for PCR with strong self-base pairing
Treatment of HDV (as per EASL)
All patients with compensated liver disease (irrespective of cirrhosis)
48 week course for pegIFNa (not licensed for HDV)
Can give both pegIFNa and bulevirtide (better response)
Just bulevirtide in patients with IFN intolerability
Mechanism of action of bulevirtide
Sodium-bile acid co-transporter inhibitor (entry inhibitor)
Contains 47 aa of the preS1 domain of HBV large surface protein so blocks entry as binds NTCP receptor
Does not inhibit HDV cell-cell spread
Most common side effects of bulevirtide
Raised level of bile salts in blood and reaction at infection site
Treatment monitoring for HDV (EASL)
Test RNA every 6 m
After discontinuation of treatment with IFN, test at 6 m, 12m and yearly thereafter
After discontinuation of treatment with BLV, test at 1 m, 3 m, 6 m, 12 m and yearly thereafter
Eligibility of bulevirtide for CHD (NICE)
Adults with compensated liver disease AND:
Significant fibrosis >=F2
Not responded to (or cannot have) PEG-IFN
Not for use in decompensated liver disease
Specific management of HDV in pregnancy
None
Maternal HDV transmission is incredibly rare, so same strategy used as HBV monoinfection
