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Proposal for a Hepatitis A
genotype panel
Rob Anderson.
National Institute for Biological Standards and Control
Assuring the quality of biological medicines
Hepatitis A
•
Hepatitis A (HAV) is a non-enveloped, positive stranded RNA virus
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HAV is a member of the genus hepatovirus of the picornavirus family
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The genome is approximately 7.5kBp in length
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The genome has two UTRs
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The 5’ UTR is longer, being around 600-1200 BP in length, compared to that
of the 3’ UTR, which is around 40-80bp.
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Like most positive sense RNA genomes, the genetic material alone is
infectious
Hepatitis A
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Nucleotide sequence analysis of HAV has allowed classification of the virus
into six different genotypes
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Genotypes I, II, and III are associated with human infections whereas
genotypes IV, V and VI cause infections in simians
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Subtype IA appears to be responsible for the majority of HAV cases
worldwide, whereas subtype IB viruses tend to be found only in the
Mediterranean region
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There is no published clinical correlation to genotype
Hepatitis A Disease
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Hepatitis A infection-is an acute, self-limiting infection of the liver without a
chronic stage usually transmitted by the faecal-oral route
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The infection may be asymptomatic or may cause an acute hepatitis syndrome
of varying degrees of severity up to and including fulminant hepatitis.
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Peak viraemia is seen 10-12 days after infection
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This means that it is possible for donations from asymptomatic individuals to
occur as there is a short period (several days) between viraemia and
symptoms
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Hepatitis A can be transmitted by the parenteral route but very rarely
by blood and blood products
Screening for Hepatitis A
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HAV is rarely transmitted by transfusion and is much rarer in whole blood
donors than B19 (estimated to be between 1 : 500 000 - 1 000 000 donors)
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Transmission by pooled derivatives has occurred in the case of FVIII
–
Chudy et al. J Med Virol (1999) 57: 91-9
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Principle reason is that HAV is not inactivated during the manufacturing
process and is resistant to detergent, acid (pH 1), solvents, drying, and
temperatures up to 60oC
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Therefore NAT is performed for plasma intended for manufacture of blood
products/derivatives
HAV assay kits
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Two principle manufacturers of diagnostic HAV assay kits
– LightCycler Hepatitis A virus quantification kit (Roche Diagnostics)
– RealArt HAV LC RT PCR kit (Qiagen artus GmbH)
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Study was performed and published
– G Sánchez et al. J Virol Methods (2006) 132: 160-5.
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They used HM-175 (Genotype IB) and HAS15 (genotype IA)
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Conclusion was that both assays are very suitable for detection and
quantification of the most prevalent HAV subtypes
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However not all genotypes may be picked up as sensitively as each other
27 HAV isolates with complete
sequence information.
Endo et al. Virus Research 126 (2007) 116–127
Percentage comparison of the complete
ORF nucleotide and amino acid sequence
identities of 26 known HAV isolates
Endo et al. Virus Research 126 (2007) 116–127
Proposal
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As many samples of Hepatitis A positive serum/plasma as possible covering all
of the identified genotypes
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Amplification (if possible) in animals - macaques at the HPA
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NIBSC co-ordinated collaborative study to assess and validate the panel
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Genotype panel as a catalogue item analogous to the Hepatitis C panel
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The panel will be available to kit manufacturers and others intending to
validate “in-house” assays for HAV
Contact address
[email protected]
Thank you for your help.