Proceedings of a consensus conference: the screening of blood donors for variant CJD1
Section snippets
Background and epidemiology of BSE
Presented by Maura N. Ricketts, MD, MHSC, FRCP(C) World Health Organization Geneva, Switzerland
Since the identification of the first bovine spongiform encephalopathy (BSE) in the United Kingdom in 1986, there have been over 180,000 cases of BSE reported from the United Kingdom alone. Although the origin of the epidemic is uncertain, it is clear that this infection was propagated by the recycling of bovine feed. The number of BSE reports in the United Kingdom and Europe by year is detailed in
Background and epidemiology of vCJD
Presented by Richard Knight, MD National CJD Surveillance Unit, Edinburgh, United Kingdom
TSEs have been described in both humans and in animals (Table 1). CJD occurs in 4 forms: sporadic, genetic, iatrogenic, and variant. vCJD was first described in humans in 1996 and is thought to be caused by the same agent responsible for BSE in cattle.
vCJD in transfusion
Presented by Chris Prowse, MD, Research Director, Scottish National Blood Transfusion Service, Edinburgh, United Kingdom
The main concern in the field of transfusion medicine, in relation to vCJD, is whether blood donations from vCJD-infected individuals are infectious.
Sensitivity, specificity, and predictive value of screening tests
Presented by Eleftherios C. Vamvakas, MD, PhD, Canadian Blood Services, Ottawa, Ontario, Canada
Laboratory tests used to screen blood donors for the presence of transfusion-transmitted infection detect the presence of a trait ordinarily associated with the infection in a population of donors with—or without—that trait. Presence of the trait is interpreted as presence of infection and thus the ability (on the part of the donor) to transmit infection. Absence of the trait is interpreted as absence
BSE and vCJD screening tests
David Anstee, MD Bristol Institute for Transfusion Sciences, Bristol, United Kingdom
The infective agent of BSE and vCJD is thought to be an abnormal form of prion protein, PRPSc. PRPSc is the most obvious target for a diagnostic test for BSE and vCJD. Its conformation differs from the normal form of prion protein, PRPc, with beta sheet regions replacing alpha helical regions. The production of specific antibodies that would detect these conformational differences has proved to be difficult. The
Legal aspects of a vCJD testing and notification program
Presented by Kathleen Sazama, MD, Anderson Cancer Center, Houston, TX, USA
Implementation of a test for vCJD would raise a number of legal issues with respect to the test procedure itself, notification of blood donors found to be test positive (or false positive), and follow-up of recipients of previous blood components donated by those individuals. One might anticipate legal action based on the adequacy of informed consent for donation (donor) or for transfusion (patient/recipient), failure of
Donor perceptions and ethical aspects of an eventual testing and notification program
Presented by Patricia Hewitt, MD, National Blood Service (England), London, United Kingdom
In the United Kingdom, the National Blood Service (NBS) (England) expects that there will be pressure to screen the blood supply for vCJD when a screening test becomes available. Screening tests may appear before a confirmatory test becomes available and before the meaning of a positive or negative test result has been determined. To explore how donors are likely to respond to the introduction of a vCJD
Open discussion
Lead by Gilles Delage, MD, Héma-Québec, Montreal, Québec, Canada
Acknowledgements
The authors of these Proceedings would like to thank the international group of expert presenters to this Consensus Conference for both their excellent presentations and for their cooperation in reviewing the summaries of their presentations for accuracy. We would like to also acknowledge the important contributions of Lisa Markus and her colleagues of Malachite Management (Vancouver, BC, Canada) for their exquisite attention to the organizational details of this Consensus Conference, the
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This Consensus Conference took place at the Ritz Carlton Hotel in Montreal, Quebec, on March 26–28, 2003, and was chaired by Dr. Gilles Delage of Héma Québec.