S1-03-01: vCJD and blood transfusion

Abstract

Variant Creutzfeldt–Jakob disease (vCJD) is a novel human prion disease, which is causally linked to bovine spongifom encephalopathy (BSE), with human infection probably due to past exposure to high titre bovine tissues in the human food chain. The pathogenesis of vCJD includes significant levels of disease–associated prion protein deposition and infectivity in peripheral lymphoreticular tissues, raising the possibility of secondary transmission through blood transfusion. To identify whether blood transfusion is a mechanism of transmission of vCJD from person to person. A look–back study of blood transfusion in vCJD (the TMER) has been undertaken in the UK since 1997 and is a collaborative study between the National Blood Services, the National CJD Surveillance Unit and the Office of National Statistics. In December 2003 a case of vCJD was identified with a prior history of a blood transfusion derived from an individual who died of vCJD, raising the possibility that the disease was transfusion transmitted. In 2004 an individual who had previously received blood donated by a vCJD donor died of intercurrent illness but was found to have positive immunostaining for prion protein in spleen and a lymph node, suggesting sub–clinical or pre–clinical infection. This individual was a PRNP codon 129 heterozygote in contrast to all tested clinical cases of vCJD, in which the genotype has been uniformly methionine homozygous. A further case of probable transfusion–transmission of vCJD was identified in 2006. The probability of transfusion transmission of vCJD has important implications for public health and a range of measures have been taken in a number of countries to minimise the risk, most initiated prior to the identification of the cases described above. With the identification of vCJD cases with a history of blood donation in a number of other countries, it is important to consider what measures may be necessary to protect public health in relation to blood and blood derived components.