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HPA - Study results are consistent with earlier estimates of vCJD prion prevalence in Britain
The Health Protection Agency (HPA) and the UCL Institute of Neurology have conducted a sensitive examination of tonsil specimens to detect the presence of the variant Creutzfeldt-Jakob Disease (vCJD) related prion protein, and found results that are consistent with earlier estimates of vCJD prion prevalence in Britain. The findings are published today in The Journal of Pathology.
This study involved using immunohistochemistry to examine 9,160 anonymised tonsils for the presence of abnormal prions and found one sample showing evidence of prions associated with vCJD.
Study author Dr Jonathan Clewley, a HPA expert on vCJD, said: "We have used a sensitive test and the result is consistent with findings of earlier studies.
"The HPA will continue its research alongside the UCL Institute of Neurology and the Veterinary Laboratories Agency, to look at appendices by immunohistochemistry, in order to give greater confidence and accuracy to prevalence estimates of vCJD prions."
The anonymised tonsils used in this study were obtained from earlier studies - they had been removed from patients for clinical reasons and would otherwise have been discarded. Tonsils are one of a number of body tissues known to harbour abnormal prions in people who carry vCJD - other tissues where these prions can be found include the appendix.
Lead author Professor Sebastian Brandner, from the UCL Institute of Neurology, said: "Prevalence studies such as this are vitally important as they enable us to estimate the prevalence of vCJD in the population. However, it is important to understand that we do not know how good these tests are at picking up infected individuals and so the results may be an underestimate.
"They also give an indication as to the number of cases to expect in the future and the potential impact for the health service. Prion diseases can have long incubation periods, and an understanding of prevalence can help researchers devise measures to prevent further transmission of the disease."
There have been 220 clinically confirmed cases of vCJD worldwide, with the UK being most affected with 173 people having developed the disease, as a result of the epidemic of bovine spongiform encephalopathy in cattle in the 1980s. Large scale vCJD prion prevalence studies are challenging at present as there is no valid test available to screen for the vCJD prion in blood.
Notes to editors
1) The findings were published in The Journal of Pathology, in a paper entitled 'Large scale immunohistochemical examination for lymphoreticular prion protein in tonsil specimens collected in Britain', Fernandez de Marco, Linehan J, Gill O, Clewley J, Brandner S. The Journal of Pathology 2010; 222: DOI: 10.1002/path.2767.
2) 'The Journal of Pathology, published by John Wiley & Sons Ltd on behalf of the Pathological Society, can be accessed online at: www.thejournalofpathology.com. To access this article free of charge visit: http://dx.doi.org/10.1002/path.2767
3) The tonsil study used anonymised tonsils from patients in the 1961 to 1985 birth cohort.
4) Previous prevalence studies have included a 2004 study on appendices: Hilton DA, Ghani AC, Conyers L et al 'Prevalence of lymphoreticular prion protein accumulation in UK tissue samples'. The Journal of Pathology 2004; 203: 733-739, and a 2009 study by the Health Protection Agency which involved testing 63,007 tonsils - 'Prevalence of disease related prion protein in anonymous tonsil specimens in Britain: cross sectional opportunistic survey'. British Medical Journal; 338: 1442-1448
5) For more information or for media enquiries only please telephone the HPA press office on:
Kathryn Swan 020 8327 7097
Louise Brown 020 8327 7080
Eleanor Bunch 020 8327 7751
Georgina Fletcher 020 8327 6690
Emma Gilgunn Jones 020 8327 6647