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The role of scavenger receptor BI in hepatitis - eTheses Repository ...

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1 Introduction<br />

1.1 <strong>The</strong> disease.<br />

1<br />

Dur<strong>in</strong>g the 1970s specific diagnostic tests for <strong>hepatitis</strong> A, B and D virus(es)<br />

established that a significant fraction <strong>of</strong> blood transfusion acquired <strong>hepatitis</strong><br />

was caused by other uncharacterised pathogens. Evidence suggested that a<br />

s<strong>in</strong>gle agent, termed non-A non-B <strong>hepatitis</strong> virus (NANBHV), accounted for up<br />

to 90% <strong>of</strong> undiagnosed cases. NANBHV rema<strong>in</strong>ed largely uncharacterised<br />

until 1989, when it was demonstrated that cDNA, synthesised from the plasma<br />

<strong>of</strong> an <strong>in</strong>fected chimpanzee, could encode for prote<strong>in</strong>s that were recognised by<br />

antibodies from NANBH patients. <strong>The</strong> cDNA clones were found to orig<strong>in</strong>ate<br />

from an RNA genome <strong>of</strong> ~10kb conta<strong>in</strong><strong>in</strong>g a s<strong>in</strong>gle open read<strong>in</strong>g frame, this<br />

new etiological agent was named <strong>hepatitis</strong> C virus (HCV) (66, 354).<br />

Expression <strong>of</strong> HCV encoded peptides <strong>in</strong> yeast allowed the development <strong>of</strong><br />

immunoassays capable <strong>of</strong> screen<strong>in</strong>g suspected subjects and it soon became<br />

apparent that large numbers <strong>of</strong> <strong>in</strong>dividuals were <strong>in</strong>fected. <strong>The</strong> major route <strong>of</strong><br />

<strong>in</strong>fection is via contact with contam<strong>in</strong>ated blood or blood products.<br />

Consequentially HCV positive antibodies were found <strong>in</strong> up to 80% <strong>of</strong> patients<br />

receiv<strong>in</strong>g treatment for haemophilia, ~65% <strong>of</strong> those with transfusion acquired<br />

<strong>hepatitis</strong> and ~60% <strong>of</strong> <strong>in</strong>travenous drug users (201, 354). Fortunately, the<br />

advent <strong>of</strong> a reliable assay for the detection <strong>of</strong> HCV allowed the screen<strong>in</strong>g <strong>of</strong><br />

blood products, therefore reduc<strong>in</strong>g transmission.

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