Prevalence of lymphoreticular prion accumulation in UK tissue samples

The University of Edinburgh, Edinburgh, Scotland, United Kingdom
The Journal of Pathology (Impact Factor: 7.43). 07/2004; 203(3):733-9. DOI: 10.1002/path.1580
Source: PubMed


This study aims to provide an estimate of the number of individuals in the UK who may be incubating variant Creutzfeldt-Jakob disease and at risk of causing iatrogenic spread of the disease. Lymphoreticular accumulation of prion protein is a consistent feature of variant Creutzfeldt-Jakob at autopsy and has also been demonstrated in the pre-clinical phase. Immunohistochemical accumulation of prion protein in the lymphoreticular system remains the only technique that has been shown to predict neurological disease reliably in animal prion disorders. In this study, immunohistochemistry was used to demonstrate the presence of prion protein, with monoclonal antibodies KG9 and 3F4, in surgically removed tonsillectomy and appendicectomy specimens. The samples were collected from histopathology departments across the UK and anonymised prior to testing. Samples were tested from 16 703 patients (14 964 appendectomies, 1739 tonsillectomies), approximately 60% of whom were from the age group 20-29 years at operation. Twenty-five per cent of the samples were excluded from the final analyses because they contained inadequate amounts of lymphoid tissue. Three appendicectomy samples showed lymphoreticular accumulation of prion protein, giving an estimated prevalence of 3/12 674 or 237 per million (95% CI 49-692 per million). The pattern of lymphoreticular accumulation in two of these samples was dissimilar from that seen in known cases of variant Creutzfeldt-Jakob disease. Although it is uncertain whether immunohistochemical accumulation of prion protein in the lymphoreticular system is specific for variant Creutzfeldt-Jakob disease, it has not been described in any other disease, including other forms of human prion disease or a range of inflammatory and infective conditions. These findings reinforce the importance of measures taken by the UK Department of Health to reduce the risk of spread of variant Creutzfeldt-Jakob via blood products and surgical instruments, and of the urgency to proceed with large-scale screening of fresh tonsil specimens for the presence of prion protein.

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    • "Transfusion transmission of vCJD has been evidenced in four recipients of nonleukoreduced red blood cells and a number of healthy individuals have been found to harbor PrP TSE in lymphoreticular tissues (de Marco et al., 2010; Gill et al., 2013; Knight, 2010; Wadsworth et al., 2011). These findings, in a scenario where uncertainty exists in regard to the number of people incubating vCJD (Gill et al., 2013; Hilton et al., 2004), raise an enormous concern about the possible spread of TSEs via blood and blood-derived products; and highlight the need of developing reliable ante-mortem assays to diagnose affected people and animals. "
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    ABSTRACT: Transmissible spongiform encephalopathies (TSEs) most commonly known as prion diseases are invariably fatal neurological disorders that affect humans and animals. These disorders differ from other neurodegenerative conformational diseases caused by the accumulation in the brain of misfolded proteins, sometimes with amyloid properties, in their ability to infect susceptible species by various routes. While the infectious properties of amyloidogenic proteins, other than misfolded prion protein (PrPTSE), are currently under scrutiny, their potential to transmit from cell to cell, one of the intrinsic properties of the prion, has been recently shown in vitro and in vivo. Over the decades, various cell culture and laboratory animal models have been developed to study TSEs. These assays have been widely used in a variety of applications but showed to be time consuming and entailed elevated costs. Novel economic and fast alternatives became available with the development of in vitro assays that are based on the property of conformationally abnormal PrPTSE to recruit normal cellular PrPC to misfold. These include the cell-free conversion assay, protein misfolding cyclic amplification (PMCA) and quaking induced conversion assay (QuIC), of which the PMCA has been the only technology shown to generate infectious prions. Moreover, it allows indefinite amplification of PrPTSE with strain-specific biochemical and biological properties of the original molecules and under certain conditions may give rise to new spontaneously generated prions. The method also allows addressing the species barrier phenomena and assessing possible risks of animal-to-animal and animal-to-human transmission. Additionally, its unprecedented sensitivity has made possible the detection of as little as one infectious dose of PrPTSE and the biochemical identification of this protein in different tissues and biological fluids, including blood, cerebral spinal fluid (CSF), semen, milk, urine and saliva during the pre-clinical and clinical phases of the disease. The mechanistic similarities between TSEs and other conformational disorders have resulted in the adaptation of the PMCA to the amplification and detection of various amyloidogenic proteins. Here we provide a compelling discussion of the different applications of this technology to the study of TSEs and other neurodegenerative diseases.
    Full-text · Article · Nov 2014 · Virus Research
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    • "Sections of the appendix, lymph nodes, spleen and tonsil showed no evidence of abnormal PrP accumulation on routine immunohistochemistry. However, repeat immunohistochemical studies using an enhanced visualisation system showed PrP accumulation in follicular dendritic cells within the tonsil, lymph node, appendix and spleen.11 The spleen showed depletion of white pulp, with sparse follicular labelling (figure 3), which was confirmed on paraffin-embedded tissue blot studies for protease-resistant prion proteinres. "
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    ABSTRACT: A small number of patients with variant Creutzfeldt-Jakob disease (vCJD) have been treated with intraventicular pentosan polysulfate (iPPS) and extended survival has been reported in some cases. To date, there have been no reports on the findings of postmortem examination of the brain in treated patients and the reasons for the extended survival are uncertain. We report on the neuropathological findings in a case of vCJD treated with PPS. Data on survival in vCJD is available from information held at the National CJD Research and Surveillance Unit and includes the duration of illness in 176 cases of vCJD, five of which were treated with iPPS. One of these individuals, who received iPPS for 8 years and lived for 105 months, underwent postmortem examination, including neuropathological examination of the brain. The mean survival in vCJD is 17 months, with 40 months the maximum survival in patients not treated with PPS. In the 5 patients treated with PPS survival was 16 months, 45 months, 84 months, 105 months and 114 months. The patient who survived 105 months underwent postmortem examination which confirmed the diagnosis of vCJD and showed severe, but typical, changes, including neuronal loss, astrocytic gliosis and extensive prion protein (PrP) deposition in the brain. The patient was also given PPS for a short period by peripheral infusion and there was limited PrP immunostaining in lymphoreticular tissues such as spleen and appendix. Treatment with iPPS did not reduce the overall neuropathological changes in the brain. The reduced peripheral immunostaining for PrP may reflect atrophy of these tissues in relation to chronic illness rather than a treatment effect. The reason for the long survival in patients treated with iPPS is unclear, but a treatment effect on the disease process cannot be excluded.
    Full-text · Article · Feb 2014 · Journal of neurology, neurosurgery, and psychiatry
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    • "The BSE prion is an epizootic agent and causes variant Creutzfeldt-Jakob disease (vCJD) in humans after dietary exposure (1–4). Because the time lag between exposure and development of vCJD may be decades, uncertainty about the extent of the pathogenicity of BSE for humans continues (5), and subclinical forms of infection may exist (6,7). A recent immunohistochemical study that estimated prevalence of prion infection in the UK population by screening samples from surgically removed appendixes found 1 in 2,000 persons were positive for the disease-associated form of the prion protein (PrP) (8). "
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    ABSTRACT: Public and animal health controls to limit human exposure to animal prions are focused on bovine spongiform encephalopathy (BSE), but other prion strains in ruminants may also have zoonotic potential. One example is atypical/Nor98 scrapie, which evaded statutory diagnostic methods worldwide until the early 2000s. To investigate whether sheep infected with scrapie prions could be another source of infection, we inoculated transgenic mice that overexpressed human prion protein with brain tissue from sheep with natural field cases of classical and atypical scrapie, sheep with experimental BSE, and cattle with BSE. We found that these mice were susceptible to BSE prions, but disease did not develop after prolonged postinoculation periods when mice were inoculated with classical or atypical scrapie prions. These data are consistent with the conclusion that prion disease is less likely to develop in humans after exposure to naturally occurring prions of sheep than after exposure to epizootic BSE prions of ruminants.
    Full-text · Article · Nov 2013 · Emerging Infectious Diseases
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