Study results consistent with earlier estimates of vCJD prion prevalence in Britain
8 October 2010
The Health Protection Agency (HPA) and a team from the Department of Neurodegenerative Disease 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.
This study, published in the Journal of Pathology, 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, an HPA expert on vCJD, said: “We have used a sensitive test and the result is consistent with findings of earlier studies."
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, 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.
reference>>de Marco, M. F., Linehan, J., Gill, O. N., Clewley, J. P. and Brandner, S. , Large-scale immunohistochemical examination for lymphoreticular prion protein in tonsil specimens collected in Britain. The Journal of Pathology, n/a. doi: 10.1002/path.2767