Impact of vCJD on blood supply

Evaluating the inter-species transmission risk of amyloid beta peptide aggregates via ingestion

BACKGROUND

Recent reports suggest that amyloid beta (Aβ) peptides can exhibit prion-like pathogenic properties. Transmission of Aβ peptide and the development of associated pathologies after surgeries with contaminated instruments and intravenous or intracerebral inoculations have now been reported across fish, rodents, primates, and humans. This raises a worrying prospect of Aβ peptides also having other characteristics typical of prions, such as evasion of the digestive process. We asked if such transmission of Aβ aggregates via ingestion was possible.

METHODS

We made use of a transgenic Drosophila melanogaster line expressing human Aβ peptide prone to aggregation. Fly larvae were fed to adult zebrafish under two feeding schemes. The first was a short-term, high-intensity scheme over 48 h to determine transmission and retention in the gut. The second, long-term scheme specifically examined retention and accumulation in the brain. The gut and brain tissues were examined by histology, western blotting, and mass spectrometric analyses.

RESULTS

None of the analyses could detect Aβ aggregates in the guts of zebrafish following ingestion, despite being easily detectable in the feed. Additionally, there was no detectable accumulation of Aβ in the brain tissue or development of associated pathologies after prolonged feeding.

CONCLUSIONS

While human Aβ aggregates do not appear to be readily transmissible by ingestion across species, two prospects remain open. First, this mode of transmission, if occurring, may stay below a detectable threshold and may take much longer to manifest. A second possibility is that the human Aβ peptide is not able to trigger self-propagation or aggregation in other species. Either possibility requires further investigation, taking into account the possibility of such transmission from agricultural species used in the food industry.

Absence of classical and atypical (H- and L-) BSE infectivity in the blood of bovines in the clinical end stage of disease as confirmed by intraspecies blood transfusion

While the presence of bovine spongiform encephalopathy (BSE) infectivity in the blood of clinically affected sheep has been proven by intraspecies blood-transfusion experiments, this question has remained open in the case of BSE-affected cattle. Although the absence of infectivity can be anticipated from the restriction of the agent to neuronal tissues in this species, evidence for this was still lacking. This particularly concerns the production and use of medicinal products and other applications containing bovine blood or preparations thereof. We therefore performed a blood-transfusion experiment from cattle in the clinical end stage of disease after experimental challenge with either classical (C-BSE) or atypical (H- and l-) BSE into calves at 4–6 months of age. The animals were kept in a free-ranging group for 10 years. Starting from 24 months post-transfusion, a thorough clinical examination was performed every 6 weeks in order to detect early symptoms of a BSE infection. Throughout the experiment, the clinical picture of all animals gave no indication of a BSE infection. Upon necropsy, the brainstem samples were analysed by BSE rapid test as well as by the highly sensitive Protein Misfolding Cyclic Amplification (PMCA), all with negative results. These results add resilient data to confirm the absence of BSE infectivity in the donor blood collected from C-, H- and l-BSE-affected cattle even in the final clinical phase of the disease. This finding has important implications for the risk assessment of bovine blood and blood products in the production of medicinal products and other preparations.

Donating blood for research: a potential method for enhancing customer satisfaction of permanently deferred blood donors

BACKGROUND

Each year, a large number of individuals in Australia are deferred from donating blood. A deferral may have a negative impact on donor satisfaction and subsequent word-of-mouth communication. The Australian Red Cross Blood Service (the Blood Service) is, therefore, investigating options for managing service interactions with deferred donors to maintain positive relationships. While public research institutes in Australia have established independent research donor registries, other countries provide programmes allowing deferred donors to donate blood for research via blood collection agencies. This study examined attitudes towards donating blood for research use in a sample of permanently deferred Australian donors.

MATERIALS AND METHODS

Donors permanently deferred because of a risk of variant Creutzfeldt-Jakob disease (n=449) completed a postal survey that examined attitudes towards research donation.

RESULTS

The majority of participants were interested in donating blood for research (96%), and joining a registry of research donors (93%). Participants preferred to donate for transfusion or clinical research, and were willing to travel large distances. Results indicated that positive attitudes towards the Blood Service would be extended if the opportunity to donate blood was provided. These findings indicate a desire for continued engagement with the Blood Service despite deferral.

DISCUSSION

Donating blood for research is a potential way of maintaining positive relationships with permanently deferred donors which also benefits the health research community. Through maintaining positive relationships with deferred donors, positive word-of-mouth activity can be stimulated. Further work is needed to determine the feasibility of implementing research donation through the Blood Service in Australia.

Benefit of transfusion-related acute lung injury risk-minimization measures--German haemovigilance data (2006-2010)

OBJECTIVE

Based on the frequency of immune-mediated and non-immune-mediated transfusion-related acute lung injury (TRALI), the effect of risk-minimization measures was evaluated during a period of 5 years (2006-2010). Risk-minimization measures were implemented in 2008/2009, consisting of exclusion of female donors with a history of pregnancy or exclusion of female donors with human leucocyte antigen (HLA)/human neutrophil alloantigen (HNA) antibodies.

METHODS

TRALI was confirmed according to the criteria of the International Haemovigilance Network. Based upon the results of donor testing of white-blood-cell antibodies (WBC-Ab) against HLA or HNAs, confirmed cases were classified as immune- or non-immune-mediated TRALI. Reporting rates were calculated on the basis of the annually transfused blood components, and pre- and post-implementation periods were compared.

RESULTS

In total, 60 immune-mediated (75%) and 20 non-immune-mediated (25%) TRALI reactions were confirmed. A total of 68 (64 women and four men) donors were involved: seven red-blood-cell concentrates donors (13%), six platelet concentrate donors (10%), and 48 fresh frozen plasma (FFP) donors (77%). The reporting rate of immune-mediated TRALI caused by FFP decreased continuously; from 12·71 per million units in 2006/2007 to 6·81 per million units in 2008/2009 and no case in 2010.

CONCLUSION

The comparison of the pre- and the post-implementation period demonstrated a significantly reduced risk of TRALI events comparing 2006/2007 with 2010 (P-value: <0·01). Furthermore, no case of TRALI-induced fatality occurred after the implementation of risk-minimization measures.

Consumers' understanding and concerns about bovine spongiform encephalopathy (BSE): comparison among Canadian, American, and Japanese consumers

In spite of much analysis of the impact of bovine spongiform encephalopathy (BSE) on consumer perceptions and meat purchases, there has been little explicit analysis of the level of BSE knowledge. In this study the role of knowledge about BSE was examined in Canada, the United States, and Japan. In addition, the level of knowledge was linked to human health concerns regarding BSE and whether there is agreement with paying a premium for beef with BSE animal tests. From a public policy perspective, understanding whether higher or lower knowledge is linked to public concern and desire for market intervention might help in the design of risk communication in any future animal disease outbreak. Should lack of knowledge about the disease be related to a public desire for market intervention (animal testing, for example), then an increase in detailed information about how humans might contract the disease might change public pressure for intervention. As compared to U.S. and Canadian respondents, Japanese respondents are more knowledgeable regarding the ways in which humans might be exposed to the human variant of BSE (variant Creutzfeldt-Jakob disease, vCJD) and are more concerned about the disease. However, U.S. respondents are more willing to pay a premium for beef tested to ensure that it will not result in vCJD. Japanese respondents who are more knowledgeable about BSE are more concerned about the risk of BSE to human health. In Canada, subjects who are more knowledgeable about the ways in which humans attain vCJD are less concerned about the risk of BSE to human health. Knowledge of the ways in which humans develop vCJD does not significantly influence concerns about the risk of BSE to human health in the United States or willingness to pay for BSE-tested beef in any of the three countries. The links between knowledge and concerns about BSE and between knowledge and agreement with paying premiums for BSE-tested beef were estimated for each country using ordered probit regressions.

A molecular switch controls interspecies prion disease transmission in mice

Transmissible spongiform encephalopathies are lethal neurodegenerative disorders that present with aggregated forms of the cellular prion protein (PrPC), which are known as PrPSc. Prions from different species vary considerably in their transmissibility to xenogeneic hosts. The variable transmission barriers depend on sequence differences between incoming PrPSc and host PrPC and additionally, on strain-dependent conformational properties of PrPSc. The beta2-alpha2 loop region within PrPC varies substantially between species, with its structure being influenced by the residue types in the 2 amino acid sequence positions 170 (most commonly S or N) and 174 (N or T). In this study, we inoculated prions from 5 different species into transgenic mice expressing either disordered-loop or rigid-loop PrPC variants. Similar beta2-alpha2 loop structures correlated with efficient transmission, whereas dissimilar loops correlated with strong transmission barriers. We then classified literature data on cross-species transmission according to the 170S/N polymorphism. Transmission barriers were generally low between species with the same amino acid residue in position 170 and high between those with different residues. These findings point to a triggering role of the local beta2-alpha2 loop structure for prion transmissibility between different species.

Quality and Safety in Blood Supply in 2010

The past two decades saw tremendous achievements in blood safety, which are due to the commitment of blood establishments and industry, progress in technology such as the improvement of serological and NAT screening tests, and stringent regulatory control. Milestones in the legislation were the inclusion of plasma derivatives in the pharmaceutical legislation of the European Community (EC) in the year 1989 and special laws for the blood sector in EC and in member states, such as the Transfusionsgesetz (Transfusion Law) in Germany. The legal frame has to be supplemented by scientific and technical guidance, which is provided on the European level by the European Directorate for the Quality of Medicines and Health Care and by the European Medicines Agency. In the member states, guidelines taking into account the national peculiarities can be elaborated, such as the German hemotherapy guidelines issued by the German Medical Association (Bundesärztekammer) in agreement with the Paul-Ehrlich-Institut. The regulatory control of screening tests, and the introduction of NAT testing lead to a remarkably high degree of safety concerning the most relevant viruses HIV, HBV and HCV. Issues needing further attention are bacterial contamination and transfusion-associated acute lung injury (TRALI). Measures aiming at minimizing risks have to be balanced against their impact on supply. In order to ensure the assured supply with safe blood products, sustained efforts and research are needed as well as a continuous dialogue among blood services, industry, physicians, patients and regulatory authorities.

The variant Creutzfeldt-Jakob Disease: Risk, uncertainty or safety in the use of blood and blood derivatives?

It has been long since French physician Jean-Baptiste Denys carried out the first successful blood transfusion to a human being. Using bird feathers as canules, sheep blood was transfused to a young man. The patient died soon after Denys' treatment and Denys was accused of murder. In the XXI century, known as the biotechnology century, we face new challenges in Medicine. New emerging and reemerging diseases, such as Creutzfeldt-Jakob disease (CJD) or "mad cow disease" and its human variant (vCJD), challenge the biosafety aspects of a widely extended and extremely useful technique, that is, the perfusion of blood, of its derived components and of other pharmacological products obtained from plasma. To face these new challenges we need innovative prevention strategies.

Evaluation of the human transmission risk of an atypical bovine spongiform encephalopathy prion strain

Bovine spongiform encephalopathy (BSE), the prion disease in cattle, was widely believed to be caused by only one strain, BSE-C. BSE-C causes the fatal prion disease named new variant Creutzfeldt-Jacob disease in humans. Two atypical BSE strains, bovine amyloidotic spongiform encephalopathy (BASE, also named BSE-L) and BSE-H, have been discovered in several countries since 2004; their transmissibility and phenotypes in humans are unknown. We investigated the infectivity and human phenotype of BASE strains by inoculating transgenic (Tg) mice expressing the human prion protein with brain homogenates from two BASE strain-infected cattle. Sixty percent of the inoculated Tg mice became infected after 20 to 22 months of incubation, a transmission rate higher than those reported for BSE-C. A quarter of BASE strain-infected Tg mice, but none of the Tg mice infected with prions causing a sporadic human prion disease, showed the presence of pathogenic prion protein isoforms in the spleen, indicating that the BASE prion is intrinsically lymphotropic. The pathological prion protein isoforms in BASE strain-infected humanized Tg mouse brains are different from those from the original cattle BASE or sporadic human prion disease. Minimal brain spongiosis and long incubation times are observed for the BASE strain-infected Tg mice. These results suggest that in humans, the BASE strain is a more virulent BSE strain and likely lymphotropic.