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BACKGROUND: Four recent cases of transfusion-related transmission of variant Creutzfeldt-Jakob disease (vCJD) highlight the need to develop a highly sensitive and specific screening test to detect infectivity in the blood of asymptomatic infected individuals. Protein misfolding cyclic amplification (PMCA), a method for the amplification of minute amounts of disease-associated abnormal prion protein (PrPSc) to readily detectable levels, could be incorporated into such a test provided that a suitable substrate source for routine use in human PMCA reactions can be found. STUDY DESIGN AND METHODS: With the use of seed sources from individuals with variant and sporadic CJD, the use of human platelets (PLTs) as a PMCA substrate source was evaluated. The effects of seed/substrate prion protein gene ( PRNP) codon 129 genotype compatibility on amplification efficiency and freeze-thaw on a substrate's ability to support amplification and the degree of amplification achieved by serial PMCA (sPMCA) were investigated. RESULTS: Seed/substrate PRNP codon 129 compatibility was found to have a major influence on PrPSc amplification efficiency. Individual substrates, of the same PRNP codon 129 genotype, could be pooled and stored frozen for use in subsequent PMCA reactions. A consistent 10-fold increase in PrPSc detection sensitivity was achieved after each round of sPMCA, resulting in a 10,000-fold increase in detection sensitivity after four rounds, with no evidence of de novo PrPSc production detected in the unseeded PLT substrate. CONCLUSIONS: Providing issues of seed/substrate PRNP codon 129 compatibility are taken into consideration human PLTs are a suitable, readily available, renewable substrate source for use in human PMCA applications. [ABSTRACT FROM AUTHOR]

Twenty-five years has now passed since variant Creutzfeldt-Jakob disease (vCJD) was first described in the United Kingdom (UK). Early epidemiological, neuropathological and biochemical investigations suggested that vCJD represented a new zoonotic form of human prion disease resulting from dietary exposure to the bovine spongiform encephalopathy (BSE) agent. This hypothesis has since been confirmed though a large body of experimental evidence, predominantly using animal models of the disease. Today, the clinical, pathological and biochemical phenotype of vCJD is well characterized and demonstrates a unique and remarkably consistent pattern between individual cases when compared to other human prion diseases. While the numbers of vCJD cases remain reassuringly low, with 178 primary vCJD cases reported in the UK and a further 54 reported worldwide, concerns remain over the possible appearance of new vCJD cases in other genetic cohorts and the numbers of asymptomatic individuals in the population harboring vCJD infectivity. This review will provide a historical perspective on vCJD, examining the origins of this acquired prion disease and its association with BSE. We will investigate the epidemiology of the disease along with the unique clinicopathological and biochemical phenotype associated with vCJD cases. Additionally, this review will examine the impact vCJD has had on public health in the UK and the ongoing concerns raised by this rare group of disorders. [ABSTRACT FROM AUTHOR]

Variant Creutzfeldt-Jakob disease (vCJD) was first identified in 1996 in the UK, and results from human exposure to the bovine spongiform encephalopathy (BSE) agent. vCJD has subsequently been identified in 10 additional countries, and numbers continue to increase in the UK. Unlike other human prion diseases, infectivity and the disease-associated form of the prion protein are readily detected in lymphoid tissues in vCJD. In experimental BSE infection in a sheep model, infectivity has been transmitted by blood transfusion from asymptomatic infected animals to normal recipient animals, indicating that infectivity is present in blood during the incubation period. Recently, two cases of apparent iatrogenic vCJD infection by blood transfusion from asymptomatic donors who subsequently died from vCJD have been reported from the UK. The first case resulted in clinical illness identical to other cases of vCJD, while the second case was an asymptomatic infection detected at autopsy. Sensitive means of detection of disease-associated prion protein in the blood are required in order to be employed for screening purposes, both individually at the time of blood donation, and to help ascertain future numbers of vCJD cases in the UK and beyond. [ABSTRACT FROM AUTHOR]

We report a case of preclinical variant Creutzfeldt-Jakob disease (vCJD) in a patient who died from a nonneurological disorder 5 years after receiving a blood transfusion from a donor who subsequently developed vCJD. Protease-resistant prion protein (PrPres) was detected by western blot, paraffinembedded tissue blot, and immunohistochemistry in the spleen, but not in the brain. Immunohistochemistry for prion protein was also positive in a cervical lymph node. The patient was a heterozygote at codon 129 of PRNP, suggesting that susceptibility to vCJD infection is not confined to the methionine homozygous PRNP genotype. These findings have major implications for future estimates and surveillance of vCJD in the UK. [ABSTRACT FROM AUTHOR]