Diagnostic accuracy of cerebrospinal fluid protein markers for sporadic Creutzfeldt-Jakob disease in Canada: a 6-year prospective study

The Role of Glial Cells in Neurobiology and Prion Neuropathology

Prion diseases are rare and neurodegenerative diseases that are characterized by the misfolding and infectious spread of the prion protein in the brain, causing progressive and irreversible neuronal loss and associated clinical and behavioral manifestations in humans and animals, ultimately leading to death. The brain has a complex network of neurons and glial cells whose crosstalk is critical for function and homeostasis. Although it is established that prion infection of neurons is necessary for clinical disease to occur, debate remains in the field as to the role played by glial cells, namely astrocytes and microglia, and whether these cells are beneficial to the host or further accelerate disease. Here, we review the current literature assessing the complex morphologies of astrocytes and microglia, and the crosstalk between these two cell types, in the prion-infected brain.

Role of Biomarkers for the Diagnosis of Prion Diseases: A Narrative Review

Prion diseases are progressive and irreversible neurodegenerative disorders with a low incidence (1.5–2 cases per million per year). Genetic (10–15%), acquired (anecdotal) and sporadic (85%) forms of the disease have been described. The clinical spectrum of prion diseases is very varied, although the most common symptoms are rapidly progressive dementia, cerebellar ataxia and myoclonus. Mean life expectancy from the onset of symptoms is 6 months. There are currently diagnostic criteria based on clinical phenotype, as well as neuroimaging biomarkers (magnetic resonance imaging), neurophysiological tests (electroencephalogram and polysomnogram), and cerebrospinal fluid biomarkers (14-3-3 protein and real-time quaking-induced conversion (RT-QuIC)). The sensitivity and specificity of some of these tests (electroencephalogram and 14-3-3 protein) is under debate and the applicability of other tests, such as RT-QuIC, is not universal. However, the usefulness of these biomarkers beyond the most frequent prion disease, sporadic Creutzfeldt–Jakob disease, remains unclear. Therefore, research is being carried out on new, more efficient cerebrospinal fluid biomarkers (total tau, ratio total tau/phosphorylated tau and neurofilament light chain) and potential blood biomarkers (neurofilament light chain, among others) to try to universalize access to early diagnosis in the case of prion diseases.

Sporadic Creutzfeldt-Jakob disease: Real-Time Quaking Induced Conversion (RT-QuIC) assay represents a major diagnostic advance

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare and fatal neurodegenerative disorder with an incidence of 1.5 to 2 cases per million population/year. The disease is caused by a proteinaceous infectious agent, named prion (or PrPSc), which arises from the conformational conversion of the cellular prion protein (PrPC). Once formed, PrPSc interacts with the normally folded PrPC coercing it to undergo similar structural rearrangement. The disease is highly heterogeneous from a clinical and neuropathological point of view. The origin of this variability lies in the aberrant structures acquired by PrPSc. At least six different sCJD phenotypes have been described and each of them is thought to be caused by a peculiar PrPSc strain. Definitive sCJD diagnosis requires brain analysis with the aim of identifying intracerebral accumulation of PrPSc which currently represents the only reliable biomarker of the disease. Clinical diagnosis of sCJD is very challenging and is based on the combination of several clinical, instrumental and laboratory tests representing surrogate disease biomarkers. Thanks to the advent of the ultrasensitive Real-Time Quaking-Induced Conversion (RT-QuIC) assay, PrPSc was found in several peripheral tissues of sCJD patients, sometimes even before the clinical onset of the disease. This discovery represents an important step forward for the clinical diagnosis of sCJD. In this manuscript, we present an overview of the current applications and future perspectives of RT-QuIC in the field of sCJD diagnosis.

Genetic Creutzfeldt-Jakob disease shows fatal family insomnia phenotype

We report a case of genetic Creutzfeldt-Jakob disease (gCJD), which has a clinical phenotype that is highly similar to Fatal Family Insomnia (FFI) and has a triad of Wernicke-Korsakoff syndrome (WKs) at the developmental stage of the disease. The 51-year-old male complained of sleep disorder and imbalance who had visited five different hospitals before diagnosed. A neurological examination revealed a triad of symptoms characteristic for WKs such as gaze paresis, ataxia of limbs and trunk, and memory disturbances. The disturbances increased during the course of the disease, which led to the death of the patient 18 months after the appearance of the signs. Although the patient show negative in brain magnetic resonance imaging (MRI) and 14-3-3 protein of cerebrospinal fluid (CSF), he was finally diagnosed with gCJD disease by the human prion protein (PRNP) gene mutations.

Clinical Use of Improved Diagnostic Testing for Detection of Prion Disease

Prion diseases are difficult to recognize as many symptoms are shared among other neurologic pathologies and the full spectra of symptoms usually do not appear until late in the disease course. Additionally, many commonly used laboratory markers are non-specific to prion disease. The recent introduction of second-generation real time quaking induced conversion (RT-QuIC) has revolutionized pre-mortem diagnosis of prion disease due to its extremely high sensitivity and specificity. However, RT-QuIC does not provide prognostic data and has decreased diagnostic accuracy in some rarer, atypical prion diseases. The objective of this review is to provide an overview of the current clinical utility of fluid-based biomarkers, neurodiagnostic testing, and brain imaging in the diagnosis of prion disease and to suggest guidelines for their clinical use, with a focus on rarer prion diseases with atypical features. Recent advancements in laboratory-based testing and imaging criteria have shown improved diagnostic accuracy and prognostic potential in prion disease, but because these diagnostic tests are not sensitive in some prion disease subtypes and diagnostic test sensitivities are unknown in the event that CWD transmits to humans, it is important to continue investigations into the clinical utility of various testing modalities.

Biomarkers and diagnostic guidelines for sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease is a fatal neurodegenerative disease caused by misfolded prion proteins (PrP^Sc). Effective therapeutics are currently not available and accurate diagnosis can be challenging. Clinical diagnostic criteria use a combination of characteristic neuropsychiatric symptoms, CSF proteins 14-3-3, MRI, and EEG. Supportive biomarkers, such as high CSF total tau, could aid the diagnostic process. However, discordant studies have led to controversies about the clinical value of some established surrogate biomarkers. Development and clinical application of disease-specific protein aggregation and amplification assays, such as real-time quaking induced conversion (RT-QuIC), have constituted major breakthroughs for the confident pre-mortem diagnosis of sporadic Creutzfeldt-Jakob disease. Updated criteria for the diagnosis of sporadic Creutzfeldt-Jakob disease, including application of RT-QuIC, should improve early clinical confirmation, surveillance, assessment of PrP^Sc seeding activity in different tissues, and trial monitoring. Moreover, emerging blood-based, prognostic, and potentially pre-symptomatic biomarker candidates are under investigation.

Prion Diseases

Prions diseases are uniformly fatal neurodegenerative diseases that occur in sporadic, genetic, and acquired forms. Acquired prion diseases, caused by infectious transmission, are least common. Most prion diseases are not infectious, but occur spontaneously through misfolding of normal prion proteins or genetic mutations in the prion protein gene. Although most prion diseases are not caused by infection, they can be transmitted accidentally. Certain infection control protocols should be applied when handling central nervous system and other high-risk tissues. New diagnostic methods are improving premortem and earlier diagnosis. Treatment trials have not shown improved survival, but therapies may be available soon.

Review: Fluid biomarkers in the human prion diseases

The human prion diseases are a diverse set of often rapidly progressive neurodegenerative conditions associated with abnormal forms of the prion protein. We review work to establish diagnostic biomarkers and assays that might fill other important roles, particularly those that could assist the planning and interpretation of clinical trials. The field now benefits from highly sensitive and specific diagnostic biomarkers using cerebrospinal fluid: detecting by-products of rapid neurodegeneration or specific functional properties of abnormal prion protein, with the second generation real time quaking induced conversion (RT-QuIC) assay being particularly promising. Blood has been a more challenging analyte, but has now also yielded valuable biomarkers. Blood-based assays have been developed with the potential to screen for variant Creutzfeldt-Jakob disease, although it remains uncertain whether these will ever be used in practice. The very rapid neurodegeneration of prion disease results in strong signals from surrogate protein markers in the blood that reflect neuronal, axonal, synaptic or glial pathology in the brain: notably the tau and neurofilament light chain proteins. We discuss early evidence that such tests, applied alongside robust diagnostic biomarkers, may have potential to add value as clinical trial outcome measures, predictors of future disease course (including for asymptomatic individuals at high risk of prion disease), and as rapidly accessible and sensitive markers to aid early diagnosis.

First European case of Creutzfeldt-Jakob disease with a PRNP G114V mutation

Genetic Creutzfeldt-Jakob disease is due to mutations in the PRNP gene. Only two families with a PRNP G114V mutation have been described around the world. We report the first European case, who had no family history and initially presented with isolated deficit in hippocampus-dependent memory. Initial investigations were normal except for elevated total tau protein in the cerebrospinal fluid. He died 4 years after disease onset. This case highlights the diagnostic difficulties posed by genetic Creutzfeldt-Jakob disease, and shows that genetic analyses should be considered even in sporadic cases.

Sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (CJD), the most common human prion disease, is generally regarded as a spontaneous neurodegenerative illness, arising either from a spontaneous PRNP somatic mutation or a stochastic PrP structural change. Alternatively, the possibility of an infection from animals or other source remains to be completely ruled out. Sporadic CJD is clinically characterized by rapidly progressive dementia with ataxia, myoclonus, or other neurologic signs and, neuropathologically, by the presence of aggregates of abnormal prion protein, spongiform change, neuronal loss, and gliosis. Despite these common features the disease shows a wide phenotypic variability which was recognized since its early descriptions. In the late 1990s the identification of key molecular determinants of phenotypic expression and the availability of a large series of neuropathologically verified cases led to the characterization of definite clinicopathologic and molecular disease subtypes and to an internationally recognized disease classification. By showing that these disease subtypes correspond to specific agent strain-host genotype combinations, recent transmission studies have confirmed the biologic basis of this classification. The introduction of brain magnetic resonance imaging techniques such as fluid-attenuated inversion recovery and diffusion-weighted imaging sequences and cerebrospinal fluid biomarker assays for the detection of brain-derived proteins as well as real-time quaking-induced conversion assay, allowing the specific detection of prions in accessible biologic fluids and tissues, has significantly contributed to the improved accuracy of the clinical diagnosis of sporadic CJD in recent years.

A systematic review comparing the diagnostic value of 14-3-3 protein in the cerebrospinal fluid, RT-QuIC and RT-QuIC on nasal brushing in sporadic Creutzfeldt-Jakob disease

BACKGROUND

Sporadic Creutzfeldt-Jakob disease (sCJD) is a human prion disease that is a relatively common differential diagnosis in dementia patients. Therefore it needs a good diagnostic tool. Brain autopsy is the golden standard for the diagnosis of CJD; however, a less invasive technique is 14-3-3 protein measurement in the cerebrospinal fluid (CSF). In this systematic review, we compared the diagnostic value of the 14-3-3 protein measurement to the newer RT-QuIC test and a variant of RT-QuIC where nasal brushing is used to collect the samples.

METHODS

The search via MeSH terms and quality assessment was carried out by two individual researchers.

RESULTS

In 14-3-3 and RT-QuIC the sensitivity was comparable, respectively, 88% and 86%. Specificity however was higher in RT-QuIC 99.5% compared to 80% in 14-3-3. Nasal brushing showed the best results with a sensitivity of 97% and a specificity of 100%.

CONCLUSION

Nasal brushing, despite being the best diagnostic tool according to the data, needs more study since there has only been a few studies regarding the technique. It is safe to say that due to the high specificity, RT-QuIC is superior to 14-3-3 testing.

Intérêt clinique des concentrations sériques de la protéine S100β dans l’évaluation des patients traumatisés crâniens

Les recommandations de la Société française de médecine d’urgence concernant la prise en charge des patients traumatisés crâniens légers ont été éditées en 2012, complétées par des recommandations sur la bonne utilisation du biomarqueur S100β deux ans plus tard. Grâce à son excellente valeur prédictive négative, la protéine S100β utilisée à travers des règles strictes de prescription a été définie comme une alternative solide à la tomodensitométrie. Cependant, plusieurs questions restent en suspens concernant le délai maximum de réalisation du prélèvement par rapport à l’heure du traumatisme, l’impact médicoéconomique, les variations en rapport avec l’âge du patient, l’impact des agents anticoagulants ou antiagrégants plaquettaires et l’utilité du dosage sérique de cette protéine dans d’autres cadres nosologiques.

Case series of Creutzfeldt-Jakob disease in a third-level hospital in Quito

BACKGROUND

Creutzfeldt-Jakob disease is a rare and fatal neurodegenerative disorder that affects mammals and humans. The prevalence of this disease in the United States is 0.5 to 1 per million inhabitants. So far in Ecuador, we do not know what the prevalence or incidence is, and only one case report has been written.

CASE PRESENTATION

We present a case series of Creutzfeldt-Jakob disease in a third-level hospital in Quito. The average age of symptom onset in our patients was 58.8 years. The male to female ratio was 1:1. Two patients began with cognitive/behavioral symptoms, while 4 patients began with focal neurological signs; 1 case with ataxia, 2 with gait disorders and 1 with vertigo and headache. All of the patients had the clinical features established by the World Health Organization. In addition, the entire cohort was positive for the 14-3-3 protein in cerebrospinal fluid, and had high signal abnormalities in caudate and putamen nucleus in DWI and FLAIR IRM. Only in one case, did we reach a definitive diagnosis through a pathological study. All other cases had a probable diagnosis. In this series of cases, 6 out of 6 patients died. The average time from the onset of the symptoms to death in this cohort was 13 months.

CONCLUSION

This is the first report of a series of cases of Creutzfeldt-Jakob disease in Quito. Although definitive diagnosis must be histopathological, there are ancillary tests currently available that have allowed us to obtain a diagnosis of the disease.

Altered rPrP substrate structures and their influence on real-time quaking induced conversion reactions

BACKGROUND

Bacterially-produced recombinant prion protein (rPrP) has traditionally been used for in vitro fibrillation assays and reagent development for prion disease research. In recent years, it has also been used as a substrate for real-time quaking-induced conversion (RT-QuIC), a very sensitive method of detecting the presence of the misfolded, disease-associated isoform of the prion protein (PrP^d). Multi-centre trials have demonstrated that RT-QuIC is a suitably reliable and robust technique for clinical practice; however, in the absence of a commercial supplier of rPrP as a substrate for RT-QuIC, laboratories have been required to independently generate this key component of the assay. No harmonized method for producing the protein has been agreed upon, in part due to the variety of substrates that have been applied in RT-QuIC.

METHODS

This study examines the effects of two different rPrP refolding protocols on the production, QuIC performance, and structure characteristics of two constructs of rPrP commonly used in QuIC: full length hamster and a sheep-hamster chimeric rPrP.

RESULTS

Under the described conditions, the best performing substrate was the chimeric sheep-hamster rPrP produced by shorter guanidine-HCl exposure and faster gradient elution.

CONCLUSIONS

The observation that different rPrP production protocols influence QuIC performance indicates that caution should be exercised when comparing inter-laboratory QuIC results.

Prion-specific and surrogate CSF biomarkers in Creutzfeldt-Jakob disease: diagnostic accuracy in relation to molecular subtypes and analysis of neuropathological correlates of p-tau and Aβ42 levels

The differential diagnosis of Creutzfeldt-Jakob disease (CJD) from other, sometimes treatable, neurological disorders is challenging, owing to the wide phenotypic heterogeneity of the disease. Real-time quaking-induced prion conversion (RT-QuIC) is a novel ultrasensitive in vitro assay, which, at variance with surrogate neurodegenerative biomarker assays, specifically targets the pathological prion protein (PrP^Sc). In the studies conducted to date in CJD, cerebrospinal fluid (CSF) RT-QuIC showed good diagnostic sensitivity (82–96%) and virtually full specificity. In the present study, we investigated the diagnostic value of both prion RT-QuIC and surrogate protein markers in a large patient population with suspected CJD and then evaluated the influence on CSF findings of the CJD type, and the associated amyloid-β (Aβ) and tau neuropathology. RT-QuIC showed an overall diagnostic sensitivity of 82.1% and a specificity of 99.4%. However, sensitivity was lower in CJD types linked to abnormal prion protein (PrP^Sc) type 2 (VV2, MV2K and MM2C) than in typical CJD (MM1). Among surrogate proteins markers (14-3-3, total (t)-tau, and t-tau/phosphorylated (p)-tau ratio) t-tau performed best in terms of both specificity and sensitivity for all sCJD types. Sporadic CJD VV2 and MV2K types demonstrated higher CSF levels of p-tau when compared to other sCJD types and this positively correlated with the amount of tiny tau deposits in brain areas showing spongiform change. CJD patients showed moderately reduced median Aβ42 CSF levels, with 38% of cases having significantly decreased protein levels in the absence of Aβ brain deposits. Our results: (1) support the use of both RT-QuIC and t-tau assays as first line laboratory investigations for the clinical diagnosis of CJD; (2) demonstrate a secondary tauopathy in CJD subtypes VV2 and MV2K, correlating with increased p-tau levels in the CSF and (3) provide novel insight into the issue of the accuracy of CSF p-tau and Aβ42 as markers of brain tauopathy and β-amyloidosis.

Validation of α-Synuclein as a CSF Biomarker for Sporadic Creutzfeldt-Jakob Disease

The analysis of cerebrospinal fluid (CSF) biomarkers gains importance in the differential diagnosis of prion diseases. However, no single diagnostic tool or combination of them can unequivocally confirm prion disease diagnosis. Electrochemiluminescence (ECL)-based immunoassays have demonstrated to achieve high diagnostic accuracy in a variety of sample types due to their high sensitivity and dynamic range. Quantification of CSF α-synuclein (a-syn) by an in-house ECL-based ELISA assay has been recently reported as an excellent approach for the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD), the most prevalent form of human prion disease. In the present study, we validated a commercially available ECL-based a-syn ELISA platform as a diagnostic test for correct classification of sCJD cases. CSF a-syn was analysed in 203 sCJD cases with definite diagnosis and in 445 non-CJD cases. We investigated reproducibility and stability of CSF a-syn and made recommendations for its analysis in the sCJD diagnostic workup. A sensitivity of 98% and a specificity of 97% were achieved when using an optimal cut-off of 820 pg/mL a-syn. Moreover, we were able to show a negative correlation between a-syn levels and disease duration suggesting that CSF a-syn may be a good prognostic marker for sCJD patients. The present study validates the use of a-syn as a CSF biomarker of sCJD and establishes the clinical and pre-analytical parameters for its use in differential diagnosis in clinical routine. Additionally, the current test presents some advantages compared to other diagnostic approaches: it is fast, economic, requires minimal amount of CSF and a-syn levels are stable along disease progression.

Cerebrospinal Fluid Biomarkers in the Diagnosis of Creutzfeldt-Jakob Disease in Slovak Patients: over 10-Year Period Review

Creutzfeldt-Jakob disease is a rare, but rapidly progressive, up to now untreatable and fatal neurodegenerative disorder. Clinical diagnosis of Creutzfeldt-Jakob disease (CJD) is difficult; however, it can be facilitated by suitable biomarkers. Aim of the present study is to compare levels of cerebrospinal fluid biomarkers (total tau protein, phosphorylated-tau protein, protein 14-3-3 and amyloid beta) in Slovak population of CJD suspect cases, retrospectively in over a 10-year period. One thousand three hundred sixty-four CSF samples from patients with suspect CJD, forming a homogenous group in terms of geographical as well as of equal transport conditions, storage and laboratory processing, were analysed. Definite diagnosis of Creutzfeldt-Jakob disease was confirmed in 101 patients with genetic form, and 60 patients with its sporadic form of the disease. Specificity of protein 14-3-3 and total tau in both forms CJD was similar (87 % for P14-3-3/85 % for total tau), sensitivity to P 14-3-3 and total tau was higher in sporadic Creutzfeldt-Jakob disease (sCJD) (90/95 %) than in genetic Creutzfeldt-Jakob disease (gCJD) (89/74 %). As expected, the total tau levels were significantly higher in CJD patients than in controls, but there was also significant difference between gCJD and sCJD (levels in gCJD were lower; p = 0.003). There was no significant difference in p-tau and Aβ 1-42 levels neither between both CJD forms nor between CJD patients and control group.

Prion Diseases

PURPOSE OF REVIEW

This article presents an update on the clinical aspects of human prion disease, including the wide spectrum of their presentations.

RECENT FINDINGS

Prion diseases, a group of disorders caused by abnormally shaped proteins called prions, occur in sporadic (Jakob-Creutzfeldt disease), genetic (genetic Jakob-Creutzfeldt disease, Gerstmann-Sträussler-Scheinker syndrome, and fatal familial insomnia), and acquired (kuru, variant Jakob-Creutzfeldt disease, and iatrogenic Jakob-Creutzfeldt disease) forms. This article presents updated information on the clinical features and diagnostic methods for human prion diseases. New antemortem potential diagnostic tests based on amplifying prions in order to detect them are showing very high specificity. Understanding of the diversity of possible presentations of human prion diseases continues to evolve, with some genetic forms progressing slowly over decades, beginning with dysautonomia and neuropathy and progressing to a frontal-executive dementia with pathology of combined prionopathy and tauopathy. Unfortunately, to date, all human prion disease clinical trials have failed to show survival benefit. A very rare polymorphism in the prion protein gene recently has been identified that appears to protect against prion disease; this finding, in addition to providing greater understanding of the prionlike mechanisms of neurodegenerative disorders, might lead to potential treatments.

SUMMARY

Sporadic Jakob-Creutzfeldt disease is the most common form of human prion disease. Genetic prion diseases, resulting from mutations in the prion-related protein gene (PRNP), are classified based on the mutation, clinical phenotype, and neuropathologic features and can be difficult to diagnose because of their varied presentations. Perhaps most relevant to this Continuum issue on neuroinfectious diseases, acquired prion diseases are caused by accidental transmission to humans, but fortunately, they are the least common form and are becoming rarer as awareness of transmission risk has led to implementation of measures to prevent such occurrences.

Pulvinar sign in a case of anti-HU paraneoplastic encephalitis

This article reports the case of a 68-year-old patient with anti-HU antibodies paraneoplastic encephalitis. The clinical manifestations were atypical and the paraclinical work-up, notably the magnetic resonance imaging (MRI) showing bilateral posterior thalamic hyperintensities (pulvinar sign), misleadingly pointed towards a variant Creutzfeld-Jakob disease. After presenting the case, the differential diagnosis of the pulvinar sign is discussed along with other important diagnostic considerations.

Case Studies Illustrating Focal Alzheimer's, Fluent Aphasia, Late-Onset Memory Loss, and Rapid Dementia

Many dementia subtypes have more shared signs and symptoms than defining ones. We review 8 cases with 4 overlapping syndromes and demonstrate how to distinguish the cases. These include focal cortical presentations of Alzheimer's disease (AD; posterior cortical atrophy and corticobasal syndrome [CBS]), fluent aphasia (semantic dementia and logopenic aphasia), late-onset slowly progressive dementia (hippocampal sclerosis and limbic predominant AD) and rapidly progressive dementia (Creutzfeldt-Jakob disease and limbic encephalitis). Recognizing the different syndromes can help the clinician to improve their diagnostic skills, leading to improved patient outcomes by early and accurate diagnosis, prompt treatment, and appropriate counseling and guidance.

Epidemiological characteristics of human prion diseases

Human prion diseases are a group of transmissible, progressive, and invariably fatal neurodegenerative disorders, which include Kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome, and fatal familial insomnia. Human prion diseases affect approximately 1–2 persons per million worldwide annually, occurring in sporadic, inherited, and acquired forms. These diseases have attracted both scientific and public attention not only because of their mysterious pathogen, but also due to their considerable threat to public health since the emergence of the variant CJD.

There are still no specific therapeutic and prophylactic interventions available for prion diseases, thus active surveillance of human prion diseases is critical for disease control and prevention. Since 1993, CJD surveillance systems have been established in many countries and regions, and several long-term multinational cooperative projects have been conducted.

In this paper, the epidemiological characteristics of various human prion diseases and the active surveillance systems pertaining to them in different countries and regions are summarized and reviewed.

Biomarkers for sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare but fatal type of spongiform encephalopathy with unknown cause. Unfortunately, definitive diagnosis of this disease can only be done by examination of postmortem brain tissue. Presumptive diagnosis is done through a combination of clinical manifestations, radiology results, and cerebrospinal fluid (CSF) testing for CSF 14-3-3. Even with these guidelines, premortem diagnosis of sCJD can be unreliable with high rates of misdiagnosis. This calls for more reliable biomarkers of the disease, allowing for better diagnosis as well as understanding the pathogenesis of sCJD. This review compiles potential genetic, protein, biomolecular, and imaging biomarker studies for sCJD since 2010, highlighting the promise of proteins, cytokines, and composite biomarkers for improving the diagnosis as well as understanding the pathogenesis of this mysterious ailment.

Endpoint Quaking-Induced Conversion: a Sensitive, Specific, and High-Throughput Method for Antemortem Diagnosis of Creutzfeldt-Jacob Disease

The Prion Laboratory Section of the Public Health Agency of Canada supports heath care professionals dealing with patients suspected to have Creutzfeldt-Jakob disease (CJD) by testing cerebrospinal fluid (CSF) for protein markers of CJD. To better serve Canadian diagnostic requirements, a quaking-induced conversion (QuIC)-based assay has been added to the test panel. The QuIC tests exploit the ability of disease-associated prion protein, found in the CSF of a majority of CJD patients, to convert a recombinant prion protein (rPrP) into detectable amounts of a misfolded, aggregated form of rPrP. The rPrP aggregates interact with a specific dye, causing a measurable change in the dye's fluorescence emission spectrum. Optimal test and analysis parameters were empirically determined. Taking both practical and performance considerations into account, an endpoint QuIC (EP-QuIC) configuration was chosen. EP-QuIC uses a thermo-mixer to perform the shaking necessary to produce the quaking-induced conversions. Fluorescence readings are obtained from a microwell fluorescence reader only at the beginning and the end of EP-QuIC reactions. Samples for which the relative fluorescence unit ratio between the initial and final readings represent a ≥4 increase in signal intensity in at least two of the three replicates are classified as positive. A retrospective analysis of 91 CSF samples that included 45 confirmed cases of CJD and 46 non-CJD cases was used to estimate the performance characteristics of the EP-QuIC assay. The diagnostic sensitivity and specificity of the EP-QuIC test of this set of samples were 98 and 91%, respectively.

Sporadic Creutzfeldt-Jakob disease diagnostic accuracy is improved by a new CSF ELISA 14-3-3γ assay

Protein 14-3-3 is a reliable marker of rapid neuronal damage, specifically increased in cerebrospinal fluid (CSF) of sporadic Creutzfeldt-Jakob disease (sCJD) patients. Its detection is usually performed by Western Blot (WB), prone to methodological issues. Our aim was to evaluate the diagnostic performance of a recently developed quantitative enzyme-linked immunosorbent (ELISA) assay for 14-3-3γ, in comparison with WB and other neurodegeneration markers. CSF samples from 145 patients with suspicion of prion disease, later classified as definite sCJD (n=72) or Non-prion diseases (Non-CJD; n=73) comprised our population. 14-3-3 protein was determined by WB and ELISA. Total Tau (t-Tau) and phosphorylated Tau (p-Tau) were also evaluated. Apolipoprotein E gene (ApoE) and prionic protein gene (PRNP) genotyping was assessed. ELISA 14-3-3γ levels were significantly increased in sCJD compared to Non-CJD patients (p<0.001), showing very good accuracy (AUC=0.982; sensitivity=97%; specificity=94%), and matching WB results in 81% of all cases. It strongly correlated with t-Tau and p-Tau (p<0.0001), showing slightly higher specificity (14-3-3 WB - 63%; Tau - 90%; p-Tau/t-Tau ratio - 88%). From WB inconclusive results (n=44), ELISA 14-3-3γ correctly classified 41 patients. Additionally, logistic regression analysis selected ELISA 14-3-3γ as the best single predictive marker for sCJD (overall accuracy=93%). ApoE and PRNP genotypes did not influence ELISA 14-3-3γ levels. Despite specificity for 14-3-3γ isoform, ELISA results not only match WB evaluation but also help discrimination of inconclusive results. Our results therefore reinforce this assay as a single screening test, allowing higher sample throughput and unequivocal results.

Clinical update of Jakob-Creutzfeldt disease

PURPOSE OF REVIEW

The present review discusses recent clinical data on diagnosis, new forms, and treatment of human prion diseases, and briefly summarizes research suggesting prion-like mechanisms in other neurodegenerative diseases.

RECENT FINDINGS

When proper sequences are performed, MRI has high diagnostic utility in prion disease, but there are issues with interpretation of images. The spectrum of MRI's utility for diagnosis and understanding human prion disease is still being explored. Two recent diffusion tensor imaging studies quantified changes in the gray and white matter in sporadic Jakob-Creutzfeldt disease, with unexpected results. The diagnostic utility of cerebrospinal fluid biomarkers has been controversial. A few studies showed that amplification methods can detect prions in either cerebrospinal fluid, olfactory epithelium, blood and/or urine in various human prion diseases. Additional cases of variably protease-sensitive prionopathy have led to a broader understanding of this novel sporadic prion disease. A few new mutations causing genetic prion disease, one with a very atypical presentation, have been identified. Although recent human prion disease treatment trials did not show benefit, they have improved our understanding, and led to better quantification, of the progression of these disorders. Lastly, we briefly summarize the increasing evidence that many nonprion neurodegenerative proteinopathies might spread in the brain by a prion-like mechanism.

SUMMARY

New prion detection methods appear promising, but need to be replicated with larger sample sizes. Identification of novel forms of human prion disease might better elucidate the full spectrum of prion diseases and expand our understanding of their pathogenesis.

How many biomarkers to discriminate neurodegenerative dementia?

A number of cerebrospinal fluid (CSF) biomarkers are currently used for the diagnosis of dementia. Opposite changes in the level of amyloid-β(1-42) versus total tau and phosphorylated-tau181 in the CSF reflect the specific pathology of Alzheimer's disease (AD) in the brain. This panel of biomarkers has proven to be effective to differentiate AD from controls and from the major types of neurodegenerative dementia, and to evaluate the progression from mild cognitive impairment to AD. In the absence of specific biomarkers reflecting the pathologies of the other most common forms of dementia, such as Lewy Body disease, Frontotemporal lobar degeneration, Creutzfeldt-Jakob disease, etc., the evaluation of biomarkers of AD pathology is used, attempting to exclude rather than to confirm AD. Other biomarkers included in the common clinical practice do not clearly relate to the underlying pathology: progranulin (PGRN) is a selective marker of frontotemporal dementia with mutations in the PGRN gene; the 14-3-3 protein is a highly sensitive and specific marker for Creutzfeldt-Jakob disease, but has to be used carefully in differentiating rapid progressive dementia; and α-synuclein is an emerging candidate biomarker of the different forms of synucleinopathy. This review summarizes several biomarkers of neurodegenerative dementia validated based on the neuropathological processes occurring in brain tissue. Notwithstanding the paucity of pathologically validated biomarkers and their high analytical variability, the combinations of these biomarkers may well represent a key and more precise analytical and diagnostic tool in the complex plethora of degenerative dementia.

A new diagnostic test for Creutzfeldt-Jakob disease: Real-time quaking-induced conversion (RT-QulC)

Currently, definitive diagnoses of Creutzfeldt-Jakob disease (CJD) require an examination of the brains of deceased patients. In cooperation with an international consortium, Canada's National Microbiology Laboratory is performing a validation of a new test that can diagnose CJD in living patients. This test, the real-time quaking-induced conversion (RT-QuIC) assay, directly detects the disease associated form of the prion protein in cerebrospinal fluid. If validated, RT-QuIC will represent a major advance in the diagnoses of patients suspected to have CJD.

Comparing CSF biomarkers and brain MRI in the diagnosis of sporadic Creutzfeldt-Jakob disease

We assessed the diagnostic utility of 3 CSF biomarkers-14-3-3 protein, total tau (T-tau), and neuron-specific enolase (NSE)-from the same lumbar puncture to distinguish between participants with neuropathologically confirmed sporadic Creutzfeldt-Jakob disease (sCJD, n = 57) and controls with nonprion rapidly progressive dementia (npRPD, n = 41). Measures of diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value, as well as logistic regression and area under the receiver operator curve (AUC), were used to assess the ability of these CSF biomarkers, alone or concomitantly, to predict diagnosis. In a subcohort with available MRI (sCJD n = 57, npRPD = 32), we compared visual assessment of diffusion-weighted imaging MRI sequences to these CSF biomarkers. MRI was the best predictor, with an AUC of 0.97 (confidence interval [CI] 0.92-1.00) and a diagnostic accuracy of 97% (CI 90%-100%). Of the CSF biomarkers, T-tau had a higher diagnostic accuracy (79.6%) than 14-3-3 (70.4%, CI for difference 8.7%, 9.7%; p = 0.048) or NSE (71.4%, CI for difference 7.6%, 8.7%; p = 0.03).

CSF Biomarkers of Alzheimer’s Disease: Impact on Disease Concept, Diagnosis, and Clinical Trial Design

Data from clinicopathologic and biomarker studies have converged to support the view of Alzheimer’s disease (AD) as a continuum, with pathology developing decades prior to the onset of cognitive symptoms which culminate as dementia at the end stage of the disease. This concept is impacting disease nomenclature, diagnostic criteria, prognostic potential, and clinical trial design. Revisions to diagnostic criteria to incorporate biomarker results have recently been proposed in order to increase the confidence of AD as the underlying etiology of a clinical impairment and to permit a diagnosis of AD across the disease continuum, eventually perhaps in the asymptomatic period. Individuals in this preclinical stage are receiving intense focus as a targeted population for secondary prevention trials aimed at identifying disease-modifying therapies that have the best chance of preserving normal cognitive function. The goal is to bring validated biomarkers to clinical practice for the purpose of disease diagnosis, prognosis, and evaluation of therapeutic efficacy once disease-modifying treatments become available. Realization of this goal requires worldwide biomarker standardization efforts, consensus among researchers and clinicians regarding the clinical utility of assessing biomarkers in patient care settings, and eventually the endorsement and adoption of such procedures and practices into global health care systems.

Fit-for-purpose curated database application in mass spectrometry-based targeted protein identification and validation

Background

Mass spectrometry (MS) is a very sensitive and specific method for protein identification, biomarker discovery, and biomarker validation. Protein identification is commonly carried out by comparing MS data with public databases. However, with the development of high throughput and accurate genomic sequencing technology, public databases are being overwhelmed with new entries from different species every day. The application of these databases can also be problematic due to factors such as size, specificity, and unharmonized annotation of the molecules of interest. Current databases representing liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based searches focus on enzyme digestion patterns and sequence information and consequently, important functional information can be missed within the search output. Protein variants displaying similar sequence homology can interfere with database identification when only certain homologues are examined. In addition, recombinant DNA technology can result in products that may not be accurately annotated in public databases. Curated databases, which focus on the molecule of interest with clearer functional annotation and sequence information, are necessary for accurate protein identification and validation. Here, four cases of curated database application have been explored and summarized.

Findings

The four presented curated databases were constructed with clear goals regarding application and have proven very useful for targeted protein identification and biomarker application in different fields. They include a sheeppox virus database created for accurate identification of proteins with strong antigenicity, a custom database containing clearly annotated protein variants such as tau transcript variant 2 for accurate biomarker identification, a sheep-hamster chimeric prion protein (PrP) database constructed for assay development of prion diseases, and a custom Escherichia coli (E. coli) flagella (H antigen) database produced for MS-H, a new H-typing technique. Clearly annotating the proteins of interest was essential for highly accurate, specific, and sensitive sequence identification, and searching against public databases resulted in inaccurate identification of the sequence of interest, while combining the curated database with a public database reduced both the confidence and sequence coverage of the protein search.

Conclusion

Curated protein sequence databases incorporating clear annotations are very useful for accurate protein identification and fit-for-purpose application through MS-based biomarker validation.

Review: Laboratory diagnosis and surveillance of Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a representative human transmissible spongiform encephalopathy associated with central nervous system degeneration. Prions, the causative agents of CJD, are composed of misfolded prion proteins and are able to self-replicate. While CJD is a rare disease affecting only 1-1.5 people per million worldwide annually, it has attracted both scientific and public attention as a threatening disease since an epidemic of variant CJD (vCJD) cases appeared in the mid-1990s. Due to its unconventional transmission and invariable fatality, CJD poses a serious risk to public health. The hundreds of sporadic, genetic, and iatrogenic CJD cases as well as potential zoonotic transmission suggest that CJD is an ongoing concern for the field of medicine. Nevertheless, treatment aimed at clinical prevention and treatment that reverses the course of disease does not exist currently. Active surveillance and effective laboratory diagnosis of CJD are, therefore, critical. In this report, the surveillance systems and laboratory tests used currently to diagnose CJD in different countries are reviewed. The current efforts to improve surveillance and diagnosis for CJD using molecular and biochemical findings are also described.

Determination of neuronal antibodies in suspected and definite Creutzfeldt-Jakob disease

IMPORTANCE

Creutzfeldt-Jakob disease (CJD) and autoimmune encephalitis with antibodies against neuronal surface antigens (NSA-abs) may present with similar clinical features. Establishing the correct diagnosis has practical implications in the management of care for these patients.

OBJECTIVE

To determine the frequency of NSA-abs in the cerebrospinal fluid of patients with suspected CJD and in patients with pathologically confirmed (ie, definite) CJD.

DESIGN, SETTING, AND PARTICIPANTS

A mixed prospective (suspected) and retrospective (definite) CJD cohort study was conducted in a reference center for detection of NSA-abs. The population included 346 patients with suspected CJD and 49 patients with definite CJD.

MAIN OUTCOMES AND MEASURES

Analysis of NSA-abs in cerebrospinal fluid with brain immunohistochemistry optimized for cell-surface antigens was performed. Positive cases in the suspected CJD group were further studied for antigen specificity using cell-based assays. All definite CJD cases were comprehensively tested for NSA-abs, with cell-based assays used for leucine-rich glioma-inactivated 1 (LGI1), contactin-associated protein-like 2 (CASPR2), N-methyl-d-aspartate (NMDA), and glycine (GlY) receptors.

RESULTS

Neuronal surface antigens were detected in 6 of 346 patients (1.7%) with rapid neurologic deterioration suggestive of CJD. None of these 6 patients fulfilled the diagnostic criteria for probable or possible CJD. The target antigens included CASPR2, LGI1, NMDAR, aquaporin 4, Tr (DNER [δ/notch-like epidermal growth factor-related receptor]), and an unknown protein. Four of the patients developed rapidly progressive dementia, and the other 2 patients had cerebellar ataxia or seizures that were initially considered to be myoclonus without cognitive decline. The patient with Tr-abs had a positive 14-3-3 test result. Small cell lung carcinoma was diagnosed in the patient with antibodies against an unknown antigen. All patients improved or stabilized after appropriate treatment. None of the 49 patients with definite CJD had NSA-abs.

CONCLUSIONS AND RELEVANCE

A low, but clinically relevant, number of patients with suspected CJD had potentially treatable disorders associated with NSA-abs. In contrast, none of 49 patients with definite CJD had NSA-abs, including NMDAR-abs, GlyR-abs, LGI1-abs, or CASPR2-abs. These findings suggest that cerebrospinal fluid NSA-abs analysis should be included in the diagnostic workup of patients with rapidly progressive central nervous system syndromes, particularly when they do not fulfill the diagnostic criteria of probable or possible CJD.

Exploring physical and chemical factors influencing the properties of recombinant prion protein and the real-time quaking-induced conversion (RT-QuIC) assay

Real-time quaking-induced conversion (RT-QuIC), a highly specific and sensitive assay able to detect low levels of the disease-inducing isoform of the prion protein (PrP^d) in brain tissue biopsies and cerebral spinal fluid, has great potential to become a method for diagnosing prion disease ante mortem. In order to standardize the assay method for routine analysis, an understanding of how physical and chemical factors affect the stability of the recombinant prion protein (rPrP) substrate and the RT-QuIC assay’s sensitivity, specificity, and reproducibility is required. In this study, using sporadic Creutzfeldt-Jakob Disease brain homogenate to seed the reactions and an in vitro-expressed recombinant prion protein, hamster rPrP, as the substrate, the following factors affecting the RT-QuIC assay were examined: salt and substrate concentrations, substrate storage, and pH. Results demonstrated that both the generation of the quality and quantities of rPrP substrate critical to the reaction, as well as the RT-QuIC reaction itself required strict adherence to specific physical and chemical conditions. Once optimized, the RT-QuIC assay was confirmed to be a very specific and sensitive assay method for sCJD detection. Findings in this study indicate that further optimization and standardization of RT-QuIC assay is required before it can be adopted as a routine diagnostic test.

A low-molecular-weight ferroxidase is increased in the CSF of sCJD cases: CSF ferroxidase and transferrin as diagnostic biomarkers for sCJD

AIMS

Most biomarkers used for the premortem diagnosis of sporadic Creutzfeldt-Jakob disease (CJD) are surrogate in nature, and provide suboptimal sensitivity and specificity.

RESULTS

We report that CJD-associated brain iron dyshomeostasis is reflected in the cerebrospinal fluid (CSF), providing disease-specific diagnostic biomarkers. Analysis of 290 premortem CSF samples from confirmed cases of CJD, Alzheimer's disease, and other dementias (DMs), and 52 non-DM (ND) controls revealed a significant difference in ferroxidase (Frx) activity and transferrin (Tf) levels in sporadic Creutzfeldt-Jakob disease (sCJD) relative to other DM and ND controls. A combination of CSF Frx and Tf discriminated sCJD from other DMs with a sensitivity of 86.8%, specificity of 92.5%, accuracy of 88.9%, and area-under-the receiver-operating-characteristic (ROC) curve of 0.94. This combination provided a similar diagnostic accuracy in discriminating CJD from rapidly progressing cases who died within 6 months of sample collection. Surprisingly, ceruloplasmin and amyloid precursor protein, the major brain Frxs, displayed minimal activity in the CSF. Most of the Frx activity was concentrated in the <3-kDa fraction in normal and diseased CSF, and resisted heat and proteinase-K treatment.

INNOVATION

(i) A combination of CSF Frx and Tf provides disease-specific premortem diagnostic biomarkers for sCJD. (ii) A novel, nonenzymatic, nonprotein Frx predominates in human CSF that is distinct from the currently known CSF Frxs.

CONCLUSION

The underlying cause of iron imbalance is distinct in sCJD relative to other DMs associated with the brain iron imbalance. Thus, change in the CSF levels of iron-management proteins can provide disease-specific biomarkers and insight into the cause of iron imbalance in neurodegenerative conditions.

Ethics in prion disease

This paper is intended to discuss some of the scientific and ethical issues that are created by increased research efforts towards earlier diagnosis, as well as to treatment of, human prion diseases (and related dementias), including the resulting consequences for individuals, their families, and society. Most patients with prion disease currently are diagnosed when they are about 2/3 of the way through their disease course (Geschwind et al., 2010a; Paterson et al., 2012b), when the disease has progressed so far that even treatments that stop the disease process would probably have little benefit. Although there are currently no treatments available for prion diseases, we and others have realized that we must diagnose patients earlier and with greater accuracy so that future treatments have hope of success. As approximately 15% of prion diseases have a autosomal dominant genetic etiology, this further adds to the complexity of ethical issues, particularly regarding when to conduct genetic testing, release of genetic results, and when or if to implement experimental therapies. Human prion diseases are both infectious and transmissible; great care is required to balance the needs of the family and individual with both public health needs and strained hospital budgets. It is essential to proactively examine and address the ethical issues involved, as well as to define and in turn provide best standards of care.

Re-assessment of PrP(Sc) distribution in sporadic and variant CJD

Human prion diseases are fatal neurodegenerative disorders associated with an accumulation of PrP^Sc in the central nervous system (CNS). Of the human prion diseases, sporadic Creutzfeldt-Jakob disease (sCJD), which has no known origin, is the most common form while variant CJD (vCJD) is an acquired human prion disease reported to differ from other human prion diseases in its neurological, neuropathological, and biochemical phenotype. Peripheral tissue involvement in prion disease, as judged by PrP^Sc accumulation in the tonsil, spleen, and lymph node has been reported in vCJD as well as several animal models of prion diseases. However, this distribution of PrP^Sc has not been consistently reported for sCJD. We reexamined CNS and non-CNS tissue distribution and levels of PrP^Sc in both sCJD and vCJD. Using a sensitive immunoassay, termed SOFIA, we also assessed PrP^Sc levels in human body fluids from sCJD as well as in vCJD-infected humanized transgenic mice (Tg666). Unexpectedly, the levels of PrP^Sc in non-CNS human tissues (spleens, lymph nodes, tonsils) from both sCJD and vCJD did not differ significantly and, as expected, were several logs lower than in the brain. Using protein misfolding cyclic amplification (PMCA) followed by SOFIA, PrP^Sc was detected in cerebrospinal fluid (CSF), but not in urine or blood, in sCJD patients. In addition, using PMCA and SOFIA, we demonstrated that blood from vCJD-infected Tg666 mice showing clinical disease contained prion disease-associated seeding activity although the data was not statistically significant likely due to the limited number of samples examined. These studies provide a comparison of PrP^Sc in sCJD vs. vCJD as well as analysis of body fluids. Further, these studies also provide circumstantial evidence that in human prion diseases, as in the animal prion diseases, a direct comparison and intraspecies correlation cannot be made between the levels of PrP^Sc and infectivity.

[Unilateral Creutzfeld-Jakob disease: report of a probable case on electroclinical, MRI and biological criteria]

We report the case of a 70-year-old man who developed probable unilateral Creutzfeldt-Jakob disease. Clinically, he presented with right hemiparesis, progressive aphasia, temporospatial disorientation and cerebellar ataxia and later on, myoclonia. The MRI showed a hypersignal from the left caudate in DWI with decreased ADC. Repeated electroencephalograms showed a slow background rhythm in the left hemisphere with superimposed periodic, biphasic and triphasic sharp-wave complexes in the left temporal region. Death occurred after 5weeks. Although exceptional, unilateral Creutzfeldt-Jakob disease was retained as possible.

Cerebrospinal fluid biomarker supported diagnosis of Creutzfeldt-Jakob disease and rapid dementias: a longitudinal multicentre study over 10 years

To date, cerebrospinal fluid analysis, particularly protein 14-3-3 testing, presents an important approach in the identification of Creutzfeldt–Jakob disease cases. However, one special point of criticism of 14-3-3 testing is the specificity in the differential diagnosis of rapid dementia. The constant observation of increased cerebrospinal fluid referrals in the national surveillance centres over the last years raises the concern of declining specificity due to higher number of cerebrospinal fluid tests performed in various neurological conditions. Within the framework of a European Community supported longitudinal multicentre study (‘cerebrospinal fluid markers’) we analysed the spectrum of rapid progressive dementia diagnoses, their potential influence on 14-3-3 specificity as well as results of other dementia markers (tau, phosphorylated tau and amyloid-β_1–42) and evaluated the specificity of 14-3-3 in Creutzfeldt–Jakob disease diagnosis for the years 1998–2008. A total of 29 022 cerebrospinal fluid samples were analysed for 14-3-3 protein and other cerebrospinal fluid dementia markers in patients with rapid dementia and suspected Creutzfeldt–Jakob disease in the participating centres. In 10 731 patients a definite diagnosis could be obtained. Protein 14-3-3 specificity was analysed for Creutzfeldt–Jakob disease with respect to increasing cerebrospinal fluid tests per year and spectrum of differential diagnosis. Ring trials were performed to ensure the comparability between centres during the reported time period. Protein 14-3-3 test specificity remained high and stable in the diagnosis of Creutzfeldt–Jakob disease during the observed time period across centres (total specificity 92%; when compared with patients with definite diagnoses only: specificity 90%). However, test specificity varied with respect to differential diagnosis. A high 14-3-3 specificity was obtained in differentiation to other neurodegenerative diseases (95–97%) and non-neurological conditions (91–97%). We observed lower specificity in the differential diagnoses of acute neurological diseases (82–87%). A marked and constant increase in cerebrospinal fluid test referrals per year in all centres did not influence 14-3-3 test specificity and no change in spectrum of differential diagnosis was observed. Cerebrospinal fluid protein 14-3-3 detection remains an important test in the diagnosis of Creutzfeldt–Jakob disease. Due to a loss in specificity in acute neurological events, the interpretation of positive 14-3-3 results needs to be performed in the clinical context. The spectrum of differential diagnosis of rapid progressive dementia varied from neurodegenerative dementias to dementia due to acute neurological conditions such as inflammatory diseases and non-neurological origin.

Alzheimer's disease dementia as the diagnosis best supported by the cerebrospinal fluid biomarkers: difference in cut-off levels from thai experience

Objectives. To determine how beta-amyloid 1-42 (Aβ 1-42), total tau (tTau), and phosphorylated tau (pTau) levels in CSF behave in a cohort of Thai patients from the Memory Clinic in Bangkok, Thailand. Methods. During 2009–2011, twenty eight subjects from the memory clinic at Siriraj Hospital had CSF analysis for AD biomarkers. Aβ 1-42, tTau, and pTau (at amino acid 181) were measured in CSF by ELISA technique. Results. Mean of Thai mental state examination (TMSE) of 28 Thai cohort was 16.48 (6.63). Fourteen had AD, ten had non-AD dementia, and four non-cases were those with subjective memory complaint (SMC) without dementia. Mean CSF Aβ 1-42, tTau, ptau (181), and pTau/Aβ 1-42 in the AD group were 241.36 (60.14) pg/mL, 222.79 (212.24) pg/mL, 40.79 (27.84) pg/mL, and 0.18 (0.12) accordingly. Mean CSF Aβ 1-42, tTau, pTau (181), and pTau/Aβ 1-42 in the non-AD dementia group were 430.40 (125.18) pg/mL, 349.30 (692.16) pg/mL, 36.80 (14.90) pg/mL, and 0.09 (0.04) accordingly. Mean CSF Aβ 1-42, tTau, pTau (181), and pTau/Aβ 1-42 in the non-cases with SMC without dementia were 499.75 (93.44) pg/mL, 137.25 (62.74) pg/mL, 31.75 (17.48) pg/mL, and 0.06 (0.02). There is significant difference (P < 0.05) among the 3 groups in CSF Aβ 1-42 and pTau/Aβ 1-42. We propose mean + 1.5 SD of CSF Aβ 1-42 in AD group (331.57 pg/mL) to be the cut-off point in Thai subjects. Conclusion. There are significant different in CSF Aβ 1-42 and CSF p-tau/Aβ 1-42 among those with AD, non-AD dementia and non cases with SMC without dementia in Thai cohort. Cut-off point of CSF Aβ 1-42 of 331.57 pg/mL is suggested in Thai study.