vCJD Patients Research Articles

Development of a sensitive real-time quaking-induced conversion (RT-QuIC) assay for application in prion-infected blood.

Efforts to prevent human-to-human transmission of variant Creutzfeldt-Jakob disease (vCJD) by contaminated blood would be aided by the development of a sensitive diagnostic test that could be routinely used to screen blood donations. As blood samples from vCJD patients are extremely rare, here we describe the optimisation of real-time quaking-induced conversion (RT-QuIC) for detection of PrPSc (misfolded prion protein, a marker of prion infection) in blood samples from an established large animal model of vCJD, sheep experimentally infected with bovine spongiform encephalopathy (BSE). Comparative endpoint titration experiments with RT-QuIC, miniaturized bead protein misfolding cyclic amplification (mb-PMCA) and intracerebral inoculation of a transgenic mouse line expressing sheep PrP (tgOvARQ), demonstrated highly sensitive detection of PrPSc by RT-QuIC in a reference sheep brain homogenate. Upon addition of a capture step with iron oxide beads, the RT-QuIC assay was able to detect PrPSc in whole blood samples from BSE-infected sheep up to two years before disease onset. Both RT-QuIC and mb-PMCA also demonstrated sensitive detection of PrPSc in a reference vCJD-infected human brain homogenate, suggesting that either assay may be suitable for application to human blood samples. Our results support the further development and evaluation of RT-QuIC as a diagnostic or screening test for vCJD.

Wide distribution of prion infectivity in the peripheral tissues of vCJD and sCJD patients

Sporadic Creutzfeldt-Jakob disease (sCJD) is the commonest human prion disease, occurring most likely as the consequence of spontaneous formation of abnormal prion protein in the central nervous system (CNS). Variant Creutzfeldt–Jakob disease (vCJD) is an acquired prion disease that was first identified in 1996. In marked contrast to vCJD, previous investigations in sCJD revealed either inconsistent levels or an absence of PrPSc in peripheral tissues. These findings contributed to the consensus that risks of transmitting sCJD as a consequence of non-CNS invasive clinical procedures were low. In this study, we systematically measured prion infectivity levels in CNS and peripheral tissues collected from vCJD and sCJD patients. Unexpectedly, prion infectivity was detected in a wide variety of peripheral tissues in sCJD cases. Although the sCJD infectivity levels varied unpredictably in the tissues sampled and between patients, these findings could impact on our perception of the possible transmission risks associated with sCJD.

Human prion disease surveillance in Spain, 1993-2018: an overview

ABSTRACT In Spain, human transmissible spongiform encephalopathies (TSEs) have been undergoing continuous surveillance for over 25 years. In 1995, the system was launched as an EU Concerted Action, with EU surveillance network procedures being incorporated from 2002 onwards. The aim of this report was to describe performance and outcomes of this surveillance system across the period 1993–2018. Neurology and public health specialists from every region reported cases to a central hub at the Carlos III Health Institute, Madrid. In all, eight accidentally transmitted cases and five definite variant Creutzfeldt-Jakob disease (vCJD) patients were reported. All vCJD cases were diagnosed between 2005 and 2008. Two of these were family/dietary-related and spatially linked to a third. Yearly incidence of sporadic CJD per million was 1.25 across the period 1998–2018, and displayed a north-south gradient with the highest incidence in La Rioja, Navarre and the Basque Country. Genetic TSEs were observed to be clustered in the Basque Country, with a 4-fold incidence over the national rate. A total of 120 (5.6%) non-TSE sporadic, conformational, rapidly progressing neurodegenerative and vascular brain disorders were reported as suspect CJD. We conclude that TSEs in Spain displayed geographically uneven, stable medium incidences for the sporadic and genetic forms, a temporal and spatial family cluster for vCJD, and decreasing numbers for dura-mater-associated forms. The vCJD surveillance, framed within the EU network, might require continuing to cover all prion disorders. There is need for further strategic surveillance research focusing on case definition of rapid-course, conformational encephalopathies and surgical risk.

Preclinical Detection of Prions in Blood of Nonhuman Primates Infected with Variant Creutzfeldt-Jakob Disease.

Variant Creutzfeldt-Jakob disease (vCJD) is caused by prion infection with bovine spongiform encephalopathy and can be transmitted by blood transfusion. Protein misfolding cyclic amplification (PMCA) can detect prions in blood from vCJD patients with 100% sensitivity and specificity. To determine whether PMCA enables prion detection in blood during the preclinical stage of infection, we performed a blind study using blood samples longitudinally collected from 28 control macaques and 3 macaques peripherally infected with vCJD. Our results demonstrate that PMCA consistently detected prions in blood during the entire preclinical stage in all infected macaques, without false positives from noninfected animals, when using the optimized conditions for amplification of macaque prions. Strikingly, prions were detected as early as 2 months postinoculation (>750 days before disease onset). These findings suggest that PMCA has the potential to detect vCJD prions in blood from asymptomatic carriers during the preclinical phase of the disease.

PMCA-replicated PrPD in urine of vCJD patients maintains infectivity and strain characteristics of brain PrPD: Transmission study

The presence of abnormal, disease-related prion protein (PrPD) has recently been demonstrated by protein misfolding cyclic amplification (PMCA) in urine of patients affected with variant Creutzfeldt-Jakob disease (vCJD), a prion disease typically acquired from consumption of prion contaminated bovine meat. The complexity and multistage process of urine excretion along with the obligatory use of PMCA raise the issue of whether strain characteristics of the PrPD present in vCJD brains, such as infectivity and phenotype determination, are maintained in urine excreted PrPD and following amplification by PMCA. We inoculated transgenic mice expressing normal human PrP with amplified urine and brain homogenate achieving the same 100% attack rate, similar incubation periods (in both cases extremely long) and histopathological features as for type and severity of the lesions. Furthermore, PrPD characteristics analyzed by immunoblot and conformational stability immunoassay were indistinguishable. Inoculation of raw vCJD urine caused no disease, confirming the extremely low concentration of PrPD in vCJD urine. These findings show that strain characteristics of vCJD brain PrPD, including infectivity, are preserved in PrPD present in urine and are faithfully amplified by means of PMCA; moreover, they suggest that the PrPD urine test might allow for the diagnosis and identification of disease subtype also in sporadic CJD.

Reducing the risk of iatrogenic Creutzfeldt–Jakob disease by improving the cleaning of neurosurgical instruments

In all, there have been 178 variant Creutzfeldt-Jakob disease (vCJD) patients diagnosed in the UK, with an estimated maximum 1:2000 carriage rate based on archived appendix and tonsil tissue, implying that infection may be rare but carriage relatively frequent. Previous workers have identified that maintenance of surgical instruments in a humid atmosphere after use and prior to cleaning assists cleaning efficacy. Recently the Department of Health/Advisory Committee on Dangerous Pathogens UK have recommended a surgical instrument cleanliness threshold post cleaning of <5μg protein per instrument side. To quantify cleanliness of neurosurgical instruments and to investigate cost-effective measures for improved cleaning. Two instrument protein quantification methods were used: one based on the International Standard (15883 series) using sodium dodecyl sulphate elution and ortho-phthalaldehyde reaction, and a second in-situ protein fluorescence detection system (ProReveal) providing results per instrument side. In-vitro investigation of the efficacy of some commercial and in-house pre-clean wetting agents was undertaken using artificial test soil and stainless steel discs under standard conditions. In-vivo evaluation of best-performing in-vitro agents was undertaken on craniotomy sets. ProReveal technology demonstrated that 163 out of 187 (87%) neurosurgical instruments had <5μg residual protein per instrument side. The use of proprietary National Health Service plastic bags and sterile water-soaked wound pads were equivalent in efficacy to commercial pre-cleaning wetting products and significantly less expensive. Although we demonstrate low in-situ protein levels on neurosurgical instruments and the beneficial effects of keeping instruments moist, other cleaning critical-control points such as instrument loading patterns should also be monitored.

Hemoglobin mRNA Changes in the Frontal Cortex of Patients with Neurodegenerative Diseases.

Background: Hemoglobin is the major protein found in erythrocytes, where it acts as an oxygen carrier molecule. In recent years, its expression has been reported also in neurons and glial cells, although its role in brain tissue remains still unknown. Altered hemoglobin expression has been associated with various neurodegenerative disorders. Here, we investigated hemoglobin mRNA levels in brains of patients affected by variant, iatrogenic, and sporadic forms of Creutzfeldt-Jakob disease (vCJD, iCJD, sCJD, respectively) and in different genetic forms of prion diseases (gPrD) in comparison to Alzheimer's disease (AD) subjects and age-matched controls.Methods: Total RNA was obtained from the frontal cortex of vCJD (n = 20), iCJD (n = 11), sCJD (n = 23), gPrD (n = 30), and AD (n = 14) patients and age-matched controls (n = 30). RT-qPCR was performed for hemoglobin transcripts HBB and HBA1/2 using four reference genes for normalization. In addition, expression analysis of the specific erythrocyte marker ALAS2 was performed in order to account for blood contamination of the tissue samples. Hba1/2 and Hbb protein expression was then investigated with immunofluorescence and confocal microscope analysis.Results: We observed a significant up-regulation of HBA1/2 in vCJD brains together with a significant down-regulation of HBB in iCJD. In addition, while in sporadic and genetic forms of prion disease hemoglobin transcripts did not shown any alterations, both chains display a strong down-regulation in AD brains. These results were confirmed also at a protein level.Conclusions: These data indicate distinct hemoglobin transcriptional responses depending on the specific alterations occurring in different neurodegenerative diseases. In particular, the initial site of misfolding event (central nervous system vs. peripheral tissue)—together with specific molecular and conformational features of the pathological agent of the disease—seem to dictate the peculiar hemoglobin dysregulation found in prion and non-prion neurodegenerative disorders.In addition, these results suggest that gene expression of HBB and HBA1/2 in brain tissue is differentially affected by distinct prion and prion-like aggregating protein strains. Validation of these results in more accessible tissues could prompt the development of novel diagnostic tests for neurodegenerative disorders.

An In Vivo 11C-(R)-PK11195 PET and In Vitro Pathology Study of Microglia Activation in Creutzfeldt-Jakob Disease.

Microgliosis is part of the immunobiology of Creutzfeldt-Jakob disease (CJD). This is the first report using 11C-(R)-PK11195 PET imaging in vivo to measure 18kDa translocator protein (TSPO) expression, indexing microglia activation, in symptomatic CJD patients, followed by a postmortem neuropathology comparison. One genetic CJD (gCJD) patient, two sporadic CJD (sCJD) patients, one variant CJD (vCJD) patient (mean±SD age, 47.50±15.95years), and nine healthy controls (mean±SD age, 44.00±11.10years) were included in the study. TSPO binding potentials were estimated using clustering and parametric analyses of reference regions. Statistical comparisons were run at the regional and at the voxel-wise levels. Postmortem evaluation measured scrapie prion protein (PrPSc) immunoreactivity, neuronal loss, spongiosis, astrogliosis, and microgliosis. 11C-(R)-PK11195-PET showed a significant TSPO overexpression at the cortical level in the two sCJD patients, as well as thalamic and cerebellar involvement; very limited parieto-occipital activation in the gCJD case; and significant increases at the subcortical level in the thalamus, basal ganglia, and midbrain and in the cerebellum in the vCJD brain. Along with misfolded prion deposits, neuropathology in all patients revealed neuronal loss, spongiosis and astrogliosis, and a diffuse cerebral and cerebellar microgliosis which was particularly dense in thalamic and basal ganglia structures in the vCJD brain. These findings confirm significant microgliosis in CJD, which was variably modulated in vivo and more diffuse at postmortem evaluation. Thus, TSPO overexpression in microglia activation, topography, and extent can vary in CJD subtypes, as shown in vivo, possibly related to the response to fast apoptotic processes, but reaches a large amount at the final disease course.

Modeling Variant Creutzfeldt-Jakob Disease and Its Pathogenesis in Non-human Primates.

In the early 90s', Europe was shaken by the fear that the prions from "mad cow disease" (bovine spongiform encephalopathy) would transmit the disease to humans via beef products. In 1996, the first variant Creutzfeldt-Jakob (vCJD) patients were described, and the same year our Bovine Spongiform Encephalopathy (BSE) transmission studies to cynomolgus macaques demonstrated that the BSE prion was highly infectious for primates, inducing brain lesions identical to those observed in vCJD patients. These studies provided the first experimental evidence that vCJD was BSE in humans. Subsequent studies established the BSE/vCJD-infected cynomolgus macaque as a robust model to study the pathogenesis of vCJD. We showed rapid adaptation of BSE prions to primates upon subsequent passage, and their distribution in peripheral tissues and blood. Some key studies are summarized in the present paper.

Detection of prions in blood from patients with variant Creutzfeldt-Jakob disease.

Human prion diseases are infectious and invariably fatal neurodegenerative diseases. They include sporadic Creutzfeldt-Jakob disease (sCJD), the most common form, and variant CJD (vCJD), which is caused by interspecies transmission of prions from cattle infected by bovine spongiform encephalopathy. Development of a biochemical assay for the sensitive, specific, early, and noninvasive detection of prions (PrPSc) in the blood of patients affected by prion disease is a top medical priority to increase the safety of the blood supply. vCJD has already been transmitted from human to human by blood transfusion, and the number of asymptomatic carriers of vCJD in the U.K. alone is estimated to be 1 in 2000 people. We used the protein misfolding cyclic amplification (PMCA) technique to analyze blood samples from 14 cases of vCJD and 153 controls, including patients affected by sCJD and other neurodegenerative or neurological disorders as well as healthy subjects. Our results showed that PrPSc could be detected with 100% sensitivity and specificity in blood samples from vCJD patients. Detection was possible in any of the blood fractions analyzed and could be done with as little as a few microliters of sample volume. The PrPSc concentration in blood was estimated to be ~0.5 pg/ml. Our findings suggest that PMCA may be useful for premortem noninvasive diagnosis of vCJD and to identify prion contamination of the blood supply. Further studies are needed to fully validate the technology.

Blood transmission studies of prion infectivity in the squirrel monkey (Saimiri sciureus): the Baxter study.

Four secondary transmissions of variant Creutzfeldt-Jakob disease (vCJD) infectivity have been associated with the transfusion of nonleukoreduced red blood cells collected from vCJD patients during the asymptomatic phase of the disease. Establishing efficient experimental models for assessing the risk of future transmissions of vCJD infectivity via blood transfusion is of paramount importance in view of a study of archived appendix samples in which the prevalence of asymptomatic vCJD infection in the United Kingdom was estimated at approximately 1 in 2000 of the population. In this study, we investigated transmission of vCJD and sporadic CJD (sCJD) infectivity from blood using the squirrel monkey, which is highly susceptible to experimental challenge with human prion disease. Whole blood collected from vCJD- and sCJD-infected squirrel monkeys was transfused at multiple time points into recipient squirrel monkeys. Blood recipients were euthanized approximately 7 years after their first blood transfusion. No clinical or pathologic signs of a prion disease were observed in either the sCJD- or the vCJD-transfused monkeys, and immunohistochemistry and biochemical investigations showed no PrP(TSE) in central nervous system or lymphoreticular tissues. Similarly, monkeys inoculated intracerebrally (IC) and intravenously (IV) with either buffy coat or plasma from vCJD and sCJD patients failed to develop disease. However, white blood cells from a chimpanzee-passaged strain of human Gerstmann-Sträussler-Scheinker (GSS) disease transmitted autopsy-proven disease to two IC-inoculated monkeys after incubation periods of 34 and 39 months. Blood transmits GSS but not sCJD or vCJD infectivity to IC- or IV-inoculated squirrel monkeys within a 7-year observation period.

First Demonstration of Transmissible Spongiform Encephalopathy-associated Prion Protein (PrPTSE) in Extracellular Vesicles from Plasma of Mice Infected with Mouse-adapted Variant Creutzfeldt-Jakob Disease by in Vitro Amplification

The development of variant Creutzfeldt-Jakob disease (vCJD) in three recipients of non-leukoreduced red blood cells from asymptomatic donors who subsequently developed the disease has confirmed existing concerns about the possible spread of transmissible spongiform encephalopathies (TSEs) via blood products. In addition, the presence of disease-associated misfolded prion protein (PrP(TSE)), generally associated with infectivity, has been demonstrated in the blood of vCJD patients. However, its origin and distribution in this biological fluid are still unknown. Various studies have identified cellular prion protein (PrP(C)) among the protein cargo in human blood-circulating extracellular vesicles released from endothelial cells and platelets, and exosomes isolated from the conditioned media of TSE-infected cells have caused the disease when injected into experimental mice. In this study, we demonstrate the detection of PrP(TSE) in extracellular vesicles isolated from plasma samples collected during the preclinical and clinical phases of the disease from mice infected with mouse-adapted vCJD and confirm the presence of the exosomal marker Hsp70 in these preparations.

Characterization of Variant Creutzfeldt-Jakob Disease Prions in Prion Protein-humanized Mice Carrying Distinct Codon 129 Genotypes

To date, all clinical variant Creutzfeldt-Jakob disease (vCJD) patients are homozygous for methionine at polymorphic codon 129 (129M/M) of the prion protein (PrP) gene. However, the appearance of asymptomatic secondary vCJD infection in individuals with a PRNP codon 129 genotype other than M/M and transmission studies using animal models have raised the concern that all humans might be susceptible to vCJD prions, especially via secondary infection. To reevaluate this possibility and to analyze in detail the transmission properties of vCJD prions to transgenic animals carrying distinct codon 129 genotype, we performed intracerebral inoculation of vCJD prions to humanized knock-in mice carrying all possible codon 129 genotypes (129M/M, 129M/V, or 129V/V). All humanized knock-in mouse lines were susceptible to vCJD infection, although the attack rate gradually decreased from 129M/M to 129M/V and to 129V/V. The amount of PrP deposition including florid/amyloid plaques in the brain also gradually decreased from 129M/M to 129M/V and to 129V/V. The biochemical properties of protease-resistant abnormal PrP in the brain and transmissibility of these humanized mouse-passaged vCJD prions upon subpassage into knock-in mice expressing bovine PrP were not affected by the codon 129 genotype. These results indicate that individuals with the 129V/V genotype may be more susceptible to secondary vCJD infection than expected and may lack the neuropathological characteristics observed in vCJD patients with the 129M/M genotype. Besides the molecular typing of protease-resistant PrP in the brain, transmission studies using knock-in mice carrying bovine PrP may aid the differential diagnosis of secondary vCJD infection, especially in individuals with the 129V/V genotype.

Study on clinical features in general paresis of insane, HIV ⁃ associated dementia and Creutzfeldt ⁃ Jakob disease behaved as dementia

Objective To investigate the clinical features of general paresis of insane (GPI), HIV⁃associated dementia (HAD) and Creutzfeldt ⁃ Jakob disease (CJD). Methods The clinical features, laboratory examination, electroencephalography (EEG), magnetic resonance imaging (MRI), treatment and prognosis of 19 patients (GPI, n = 8; HAD, n = 6; CJD, n = 5) were analyzed retrospectively. Results The cases of three groups had cognitive impairment. At the same time, multiple systems (pyramidal system, extrapyramidal system and cerebellar) and multiple cranial nerves were involved. In GPI patients, the results of rapid plasma regain circle card test (RPR) and treponema pallidum particle agglutination assay (TPPA) were all positive in 8 cases, venereal disease research laboratory tests (VDRL) of CSF were positive in 4 cases, and Head MRI showed encephalatrophy in 6 cases. In HAD patients, serologic tests for HIV of all cases were positive, the average protein of CSF was increased significantly and Pandy's test was positive in 2 cases, Head MRI were characterized with multiple space occupying lesions or diffuse abnormal density image. In CJD patients, CSF 14⁃3⁃3 protein showed positive in 4 patients, EEG showed diffuse slow waves in 5 case, in which 1 case showed typical periodic triphasic wave, Head MRI in 3 sporadic CJD patients (sCJD) showed swelling like changes in sulus of cortex area and 1 varaint CJD (vCJD) patient showed hockey like change in thalamencephalon. Conclusion The clinical characteristics of dementia caused by GPI, HAD or CJD are varied, and the diagnosis mainly depends on clinical features, positive findings in serum, CSF, EEG and MRI detections. DOI：10.3969/j.issn.1672⁃6731.2012.03.019

Rapid screening and confirmatory methods for biochemical diagnosis of human prion disease

Transmissible spongiform encephalopathies (TSEs) are characterised by accumulation of an abnormal isoform of prion protein (PrP sc), mainly in the brain but also in various peripheral tissues. Home-made assays consisting of non-standardised protocols are used currently for laboratory diagnosis of human TSE. The purpose of the present study was to test the ability of two commercial assays, TeSeE™ CJD ELISA and TeSeE™ Western blot, to detect PrPsc in cerebral and lymphoid tissues of TSE patients. Both tests detected a PrPsc-significant signal in the brains of 54 affected patients and not in 51 controls, yielding 100% specificity and 100% sensitivity. Furthermore, three post-mortem spleens and two pre-mortem tonsils from three patients with variant Creutzfeldt–Jakob disease (vCJD) were detected correctly. The expected PrPsc molecular patterns were found in TSE patient brain tissue and in the tonsils and spleens of the three vCJD patients. In conclusion, these rapid and robust in vitro tools were suitable for routine human TSE diagnosis and characterisation. CJD could also be diagnosed during the patient's lifetime by detection of PrPsc in the tonsil. A diagnostic strategy associating TeSeE™ CJD ELISA screening to biochemical confirmation by TeSeE™ Western blot is proposed.

Heparin enhances the cell-protein misfolding cyclic amplification efficiency of variant Creutzfeldt–Jakob disease

Highly sensitive in vitro screening tests are required to prevent the iatrogenic spread of variant Creutzfeldt–Jakob disease (vCJD). Protein misfolding cyclic amplification (PMCA) is a candidate for such a test, but the sensitivity of this method is insufficient. Polyanions were reported to enhance PMCA efficiency, but their effects on vCJD are unclear. We developed a cell-PMCA of vCJD, wherein cell lysate containing exogenously expressed human PrP was used as substrates, to investigate the effects of various sulfated polysaccharides on amplification efficiency. PrP res amounts after cell-PMCA were analyzed by western blotting. Heparin, dermatan sulfate, and dextran sulfate (average molecular weight [MW] 1400 kDa) enhanced efficiency, but dextran sulfate (average MW 8 kDa) and a heparin pentasaccharide analog had no effect. Pentosan polysulfate inhibited cell-PMCA reaction. The amplification efficiency of cell-PMCA of vCJD increased to >100-fold per round with heparin. The enhancing effects of heparin on cell-PMCA were seed dependent: it was high for vCJD, low for sporadic Creutzfeldt–Jakob disease, and low to negligible for hamster-adapted scrapie-derived 263 K. In multi-round PMCA, signals were detected at earlier rounds with heparin than without heparin, and PrP Sc in 10 −10 diluted vCJD brain was detected by the sixth round. Heparin-assisted cell-PMCA of vCJD represents a significant step toward detecting very minute amounts of PrP Sc in the body fluids of asymptomatic vCJD patients.

A pilot to examine the logistical and feasibility issues in testing deceased tissue donors for vCJD using tonsil as the analyte

Transplanted tissues have transmitted transmissible spongiform encephalopathies and in the UK there have been more cases of variant Creutzfeldt-Jakob disease (vCJD) than elsewhere in the world. A pilot study was undertaken to look at the feasibility of testing for vCJD in deceased donors using tonsillar tissue. This pilot showed that obtaining consent for removal and testing tonsil tissue was feasible. Donor eligibility for inclusion in the pilot was limited to tissue donors from the National Health Service Blood and Transplant, Tissue Services and to donors shared with the Corneal Transplant Service Eye Banks. Obtaining tonsillar tissue in the immediate post-mortem period was limited by the presence of rigor mortis. Tonsillar tissue was suitable for routine analysis for the presence of prion associated with vCJD in deceased tissue donors. Production and processing of tissue was straightforward and a low assay background was obtained from most samples. Since palatine and lingual tonsil tissue can be obtained in pairs it was possible, in the majority of cases, to set aside an intact sample for confirmatory testing if required. In one instance a sample was reactive by Western blot. However, the pattern of reactivity was not typical for that obtained from vCJD patients. Unfortunately the sample was not of sufficient quality for the confirmatory test to provide a conclusive result.

POD01 Misleading MRI in two recent patients with variant Creutzfeldt–Jakob disease emphasises the importance of tissue diagnosis

As the vCJD outbreak evolves we are alert to possible changes in the clinicopathological phenotype, investigations and genetic analysis. MRI typically shows high signal in the pulvinar nucleus on T2W...

High-b-Value Diffusion MR Imaging and Basal Nuclei Apparent Diffusion Coefficient Measurements in Variant and Sporadic Creutzfeldt-Jakob Disease

DWI using a standard b-value of 1000 s/mm(2) has emerged as the most sensitive sequence for the diagnosis of CJD. The purpose of this study was to investigate whether DWI at a high b-value (b = 3000 s/mm(2)) and ADC measurements in the basal nuclei improve the diagnosis of vCJD and sCJD compared with visual assessment of DWI at a standard b-value (b = 1000 s/mm(2)). Eight patients with vCJD, 9 patients with sCJD, and 5 healthy volunteers underwent DWI at b = 1000 s/mm(2), and 5 vCJD patients, 4 sCJD patients, and 1 growth hormone-related CJD patient underwent DWI at b = 3000 s/mm(2). Two consultant neuroradiologists performed a visual comparison of the b = 1000 and b = 3000 images. Mean MR SI and ADC values were determined for C, P, and DM thalamus ROIs bilaterally at each b-value. SI ratios for each ROI relative to white matter were calculated. In 9 out of 10 patients, the higher b-value images were more sensitive to SI change, particularly in cortex and thalamus, with higher SI ratios at b = 3000 in the DM thalamus. For sCJD at b = 1000, we found significantly lower ADC values in the C and P compared with controls (mean C ADC = 587.3 +/- 84.7 mm(2)/s in sCJD patients versus 722.7 +/- 16.6 mm(2)/s in controls; P = .007), and at b = 3000, the differences were more pronounced. In comparison, in vCJD at b = 1000, ADC values were elevated in the Pu (mean Pu ADC = 837.6 +/- 33.0 mm/s(2) in vCJD patients versus 748.0 +/- 17.3 mm/s(2) in controls; P < .001) but failed to reach significance at b = 3000. Our results demonstrate that b = 3000 DWI, being more sensitive to slowly diffusing tissue water, is more sensitive to pathology in sCJD than is conventional DWI. High-b-value DWI increases confidence in the radiologic diagnosis of human prion disease.

Variant Creutzfeldt-Jakob disease: Neuropsychological profile in an extended series of cases

Neuropsychological data on an extended series of cases of variant Creutzfeldt-Jakob Disease (vCJD) are presented, complementing earlier findings from smaller sample studies of this condition. Distinct neuropsychological features in this extended series included relatively preserved verbal knowledge, immediate verbal memory span, and elementary visual processing. This sparing contrasted with ubiquitous impairment in every vCJD patient on timed tests of verbal fluency and digit-symbol substitution. There were also high rates of impairment on tests of memory, and of visuoperceptual and visuospatial reasoning. Our findings lend support to the view that distinctive neuropsychological features may be one of the diagnostic markers of the condition.