Agreement between 18F-Florbetapir PET imaging and cerebrospinal fluid Aβ1-42, Aβ1-40, tTau and pTau measured on the LUMIPULSE G fully automated platform

Background: Association between cerebrospinal fluid (CSF)-amyloid-β (Aβ)42 and amyloid-PET measures is inconstant across the Alzheimer’s disease (AD) spectrum. However, they are considered interchangeable, along with Aβ 42/40 ratio, for defining ‘Alzheimer’s Disease pathologic change’ (A+). Objective: Herein, we further characterized the association between amyloid-PET and CSF biomarkers and tested their agreement in a cohort of AD spectrum patients. Methods: We include ed 23 patients who underwent amyloid-PET, MRI, and CSF analysis showing reduced levels of Aβ 42 within a 365-days interval. Thresholds used for dichotomization were: Aβ 42 < 640 pg/mL (Aβ 42+); pTau > 61 pg/mL (pTau+); and Aβ 42/40 < 0.069 (ADratio+). Amyloid-PET scans were visually assessed and processed by four pipelines (SPMCL, SPMAAL, FSGM, FSWC). Results: Different pipelines gave highly inter-correlated standardized uptake value ratios (SUVRs) (rho = 0.93–0.99). The most significant findings were: pTau positive correlation with SPMCL SUVR (rho = 0.56, p = 0.0063) and Aβ 42/40 negative correlation with SPMCL and SPMAAL SUVRs (rho = –0.56, p = 0.0058; rho = –0.52, p = 0.0117 respectively). No correlations between CSF-Aβ 42 and global SUVRs were observed. In subregion analysis, both pTau and Aβ 42/40 values significantly correlated with cingulate SUVRs from any pipeline (R2 = 0.55–0.59, p < 0.0083), with the strongest associations observed for the posterior/isthmus cingulate areas. However, only associations observed for Aβ 42/40 ratio were still significant in linear regression models. Moreover, combining pTau with Aβ 42 or using Aβ 42/40, instead of Aβ 42 alone, increased concordance with amyloid-PET status from 74% to 91% based on visual reads and from 78% to 96% based on Centiloids. Conclusion: We confirmed that, in the AD spectrum, amyloid-PET measures show a stronger association and a better agreement with CSF-Aβ 42/40 and secondarily pTau rather than Aβ 42 levels.

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Alzheimer’s cerebrospinal biomarkers from Lumipulse fully automated immunoassay: concordance with amyloid-beta PET and manual immunoassay in Koreans

Alzheimer s Research & Therapy ◽

10.1186/s13195-020-00767-3 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Sohee Moon ◽

Sujin Kim ◽

Sakulrat Mankhong ◽

Seong Hye Choi ◽

Manu Vandijck ◽

...

Keyword(s):

Cognitive Decline ◽

Clinical Utility ◽

Brain Aging ◽

Csf Biomarkers ◽

Rapid Progression ◽

Amyloid Pet ◽

Positron Emission ◽

Csf Biomarker ◽

Automated Immunoassay ◽

T Tau

Abstract Background Alzheimer’s disease (AD) cerebrospinal fluid (CSF) biomarker cutoffs from immunoassays with low interlaboratory variability in diverse ethnic groups are necessary for their use in clinics and clinical trials. With lack of cutoffs from fully automated immunoassay platforms in diverse races, the aim of this study is to evaluate the clinical utility of CSF AD biomarkers from the Lumipulse fully automated immunoassay based on β-amyloid (Aβ) positron emission tomography (PET) status comparing with these from two manual immunoassays, in Koreans. Methods Among 331 Korean participants enrolled from a prospective, 3-year longitudinal observational study of the validation cohort of Korean Brain Aging Study for the Early Diagnosis and Prediction of AD, 139 (29 CN, 58 SCD, 29 MCI, and 23 AD) provided CSF and 271 underwent baseline amyloid PET (n = 128 with overlapping CSF and Aβ-PET, and 143 without CSFs). Three annual cognitive and neuropsychiatric function tests were conducted. Aβ42, Aβ40, total-tau, and phosphorylated-tau181 were measured by Lumipulse fully automated immunoassay and two manual immunoassays (INNO-BIA AlzBio3, INNOTEST). Clinical utility of CSF biomarker cutoffs, based on 128 participants with Aβ-PET, was evaluated. Results Cognitive and neuropsychological scores differed significantly among the groups, with descending performance among CN>SCD>MCI>AD. Biomarker levels among immunoassays were strongly intercorrelated. We determined the Aβ-PET status in a subgroup without CSF (n = 143), and then when we applied CSF biomarker cutoffs determined based on the Aβ-PET status, the CSF biomarkers (cutoffs of 642.1 pg/mL for Aβ42, 0.060 for Aβ42/Aβ40, 0.315 for t-tau/Aβ42, and 0.051 for p-tau/Aβ42, respectively) showed good agreement with Aβ-PET (overall AUC ranges of 0.840–0.898). Use of the Aβ-PET-based CSF cutoffs showed excellent diagnostic discrimination between AD and CN (Aβ42, Aβ42/Aβ40, t-tau/Aβ42, and p-tau/Aβ42) with overall AUC ranges of 0.876–0.952. During follow-up, participants with AD-like CSF signature determined by Aβ-PET-based cutoffs from Lumipulse showed rapid progression of cognitive decline in 139 subjects, after adjustment for potential confounders, compared with those with a normal CSF signature. Conclusion CSF AD biomarkers measured by different immunoassay platforms show strong intercorrelated agreement with Aβ-PET in Koreans. The Korean-specific Aβ-PET-based CSF biomarker cutoffs measured by the Lumipulse assay strongly predicts progression of cognitive decline. The clinical utility of CSF biomarkers from fully-automated immunoassay platforms should be evaluated in larger, more diverse cohorts.

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Clinical validation of the Lumipulse G cerebrospinal fluid assays for routine diagnosis of Alzheimer’s disease

Alzheimer s Research & Therapy ◽

10.1186/s13195-019-0550-8 ◽

2019 ◽

Vol 11 (1) ◽

Cited By ~ 8

Author(s):

Maria João Leitão ◽

Anuschka Silva-Spínola ◽

Isabel Santana ◽

Veronica Olmedo ◽

Alicia Nadal ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cerebrospinal Fluid ◽

Analytical Performance ◽

Csf Biomarkers ◽

Parameter Method ◽

Routine Practice ◽

Amyloid Pet ◽

Β Amyloid ◽

T Tau

Abstract Background Ongoing efforts within the Alzheimer’s disease (AD) field have focused on improving the intra- and inter-laboratory variability for cerebrospinal fluid (CSF) biomarkers. Fully automated assays offer the possibility to eliminate sample manipulation steps and are expected to contribute to this improvement. Recently, fully automated chemiluminescence enzyme immunoassays for the quantification of all four AD biomarkers in CSF became available. The aims of this study were to (i) evaluate the analytical performance of the Lumipulse G β-Amyloid 1-42 (restandardized to Certified Reference Materials), β-Amyloid 1-40, total Tau, and pTau 181 assays on the fully automated LUMIPULSE G600II; (ii) compare CSF biomarker results of the Lumipulse G assays with the established manual ELISA assays (INNOTEST®) from the same company (Fujirebio); and (iii) establish cut-off values and the clinical performance of the Lumipulse G assays for AD diagnosis. Methods Intra- and inter-assay variation was assessed in CSF samples with low, medium, and high concentrations of each parameter. Method comparison and clinical evaluation were performed on 40 neurological controls (NC) and 80 patients with a diagnosis of probable AD supported by a follow-up ≥ 3 years and/or positive amyloid PET imaging. A small validation cohort of 10 NC and 20 AD patients was also included to validate the cut-off values obtained on the training cohort. Results The maximal observed intra-assay and inter-assay coefficients of variation (CVs) were 3.25% and 5.50%, respectively. Method comparisons revealed correlation coefficients ranging from 0.89 (for Aβ40) to 0.98 (for t-Tau), with those for Aβ42 (0.93) and p-Tau (0.94) in-between. ROC curve analysis showed area under the curve values consistently above 0.85 for individual biomarkers other than Aβ40, and with the Aβ42/40, Aβ42/t-Tau, and Aβ42/p-Tau ratios outperforming Aβ42. Validation of the cut-off values in the independent cohort showed a sensitivity ranging from 75 to 95% and a specificity of 100%. The overall percentage of agreement between Lumipulse and INNOTEST was very high (> 87.5%). Conclusions The Lumipulse G assays show a very good analytical performance that makes them well-suited for CSF clinical routine measurements. The good clinical concordance between the Lumipulse G and INNOTEST assays facilitates the implementation of the new method in routine practice.

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Alzheimer’s Cerebrospinal Biomarkers from Lumipulse Fully Automated Immunoassay: Concordance with Amyloid-Beta PET and Manual Immunoassay in Koreans

10.21203/rs.3.rs-88942/v1 ◽

2020 ◽

Author(s):

Sohee Moon ◽

Sujin Kim ◽

Sakulrat Mankhong ◽

Seong Hye Choi ◽

Manu Vandijck ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Cognitive Decline ◽

Clinical Utility ◽

Brain Aging ◽

Subjective Cognitive Decline ◽

Csf Biomarkers ◽

Rapid Progression ◽

Amyloid Pet ◽

Csf Biomarker ◽

Automated Immunoassay

Abstract Background: Universal Alzheimer’s disease (AD) cerebrospinal fluid (CSF) biomarker cutoffs from immunoassays with low interlaboratory variability could improve diagnostic accuracy and help predict disease progression. To determine the diagnostic cutoffs of CSF AD biomarkers measured with three immunoassay platforms, including fully automated Lumipulse based on b-amyloid (Ab) positron emission tomography (PET) status, to determine diagnostic utility and clinical predictability.Methods: Three hundred thirty-one Korean participants were enrolled from a prospective, 3-year longitudinal observational study of the validation cohort of Korean Brain Aging Study for the Early Diagnosis and Prediction of AD: 71 cognitively normal (CN), 99 with subjective cognitive decline (SCD), 89 with mild cognitive impairment (MCI), and 72 with AD. Among these 331 participants, 139 (29, 58, 29, and 23 from each group, respectively) provided CSF and 271 underwent baseline amyloid PET. Three annual cognitive and neuropsychiatric function tests were conducted. Ab42, Ab40, total-tau and phosphorylated-tau181 were measured by Lumipulse fully automated immunoassay and two manual immunoassays (INNO-BIA AlzBio3, INNOTEST). Clinical utility of CSF biomarker cutoffs, based on 128 participants with Ab-PET, were evaluated.Results: Cognitive and neuropsychological scores differed significantly among the groups, with descending performance among CN > SCD > MCI > AD. Biomarker levels among immunoassays were strongly intercorrelated, and using the cutoffs for Ab-PET status with maximal AD diagnostic accuracy (n = 215), the levels showed excellent agreement with Ab-PET. Use of Ab-PET-based cutoffs for CSF biomarkers showed excellent diagnostic discrimination between AD and CN (Ab42, Ab42/Ab40, t-tau/Ab42 and p-tau/Ab42) with overall AUC ranges to discriminate AD and CN (0.876–0.952). During follow-up, participants with AD-like CSF signature determined by Ab-PET-based cutoffs from Lumipulse showed rapid progression of clinical scores, after adjustment for potential confounders, compared with those with a normal CSF signature.Conclusion: CSF AD biomarkers measured by different immunoassay platforms show strong intercorrelated agreement with Ab-PET. Ab-PET-based CSF biomarker cutoffs measured by immunoassays, including the Lumipulse, strongly predict progression of cognitive decline. The clinical utility of CSF biomarkers from fully automated immunoassay platforms should be evaluated in larger, more diverse cohorts.

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Clinical utility of Cerebrospinal Fluid Biomarkers for the Diagnosis of Alzheimer’s Disease in Korea

10.21203/rs.3.rs-25971/v1 ◽

2020 ◽

Author(s):

Jongmin Lee ◽

Hyemin Jang ◽

Sung Hoon Kang ◽

Jaeho Kim ◽

Ji-Sun Kim ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cerebrospinal Fluid ◽

Clinical Utility ◽

Medical Center ◽

Csf Biomarkers ◽

Amyloid Pet ◽

Characteristic Analysis ◽

Csf Biomarker ◽

T Tau

Abstract Background Cerebrospinal fluid (CSF) biomarkers are increasingly used in clinical practice for the diagnosis of Alzheimer’s disease (AD). We aimed to 1) determine cutoff values of CSF biomarkers for AD, 2) investigate their clinical utility by estimating a concordance with amyloid positron emission tomography (PET), and 3) apply AT (amyloid/tau) classification based on CSF results. Methods We performed CSF analysis in 51 normal controls (NC), 23 amnestic mild cognitive impairment (aMCI) and 65 AD dementia (ADD) patients at the Samsung Medical Center in Korea. We tried to develop cutoff of CSF biomarkers for differentiating ADD from NC using receiver operating characteristic analysis. We also investigated a concordance between CSF and amyloid PET results and applied AT classification scheme based on CSF biomarker abnormalities to characterize our participants. Results CSF Aβ42, total tau (t-tau) and phosphorylated tau (p-tau) significantly differ across the three groups. The area under curve for the differentiation between NC and ADD was highest in t-tau/Aβ42(0.994) followed by p-tau/Aβ42(0.963), Aβ42(0.960) and t-tau (0.918). The concordance rate between CSF Aβ42 and amyloid PET results was 92%. Finally, AT classification based on CSF biomarker abnormalities led to a majority of NC categorized into A-T-(72%), aMCI as A + T-(52%)/A + T+(30%), and AD as A + T+(56%)/A + T-(41%). Conclusion CSF biomarkers had high sensitivity and specificity in differentiating ADD from NC and were as accurate as amyloid PET. The AT group distribution was comparable to those of previous studies, which may serve to predict the prognosis more accurately than amyloid PET alone in the future.

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Pathophysiology of Alzheimer Disease

10.2310/neuro.1335 ◽

2017 ◽

Author(s):

David Knopman

Keyword(s):

Cerebrospinal Fluid ◽

Alzheimer Disease ◽

Cortical Thickness ◽

Hippocampal Volume ◽

Csf Biomarkers ◽

Amyloid Pet ◽

Symptomatic Disease ◽

18F Fluorodeoxyglucose ◽

Β Amyloid ◽

Cortical Association Areas

Genetic discoveries coupled with neuropathologic investigations initially established the central role for β-amyloidosis in Alzheimer disease (AD). Three dominantly inherited genes (APP, PSEN1, and PSEN2) and one common allelic variant with lower penetrance (APOE) account for the majority of the genetic basis for AD. PET biomarkers for AD have been developed in the past decade and are fundamentally altering our view of the disease. The availability of PET tracers, first for amyloid and now for tau, has enabled researchers to develop a model of AD that begins long before people become symptomatic. In persons destined to develop dementia due to AD, brain β-amyloid levels begin to rise 10 to 20 years earlier. Other imaging changes that might precede symptomatic disease include (1) reductions in brain metabolic activity in a group of temporal and parietal cortical association areas that can be demonstrated by [18F]fluorodeoxyglucose-PET scanning; (2) losses of hippocampal volume as measured on structural magnetic resonance imaging; and (3) loss of cortical thickness or cortical volume in temporal and parietal cortical association areas. All of these changes are greatly accentuated once people become symptomatic. Although mild elevations in tau PET abnormalities can also be seen in presymptomatic individuals, it is only when persons become symptomatic that marked elevations in these abnormalities begin to occur in those same temporal and parietal cortical association areas. Cerebrospinal fluid (CSF) biomarkers provide a complementary view, with CSF β-amyloid levels falling (presumably due to aggregation within the cortex) even before amyloid PET abnormalities are visible. CSF total tau and phospho-tau levels begin to rise when persons are much closer to being symptomatic. The sum of these observations has allowed researchers to gain a far more insightful antemortem view of the pathophysiology of AD in humans than had previously been available from neuropathologic investigations. Keywords: β-amyloid, cerebrospinal fluid β-amyloid, cerebrospinal fluid phospho-tau, cortical thickness, [18F]fluorodeoxyglucose–positron emission tomography, hippocampal atrophy, preclinical Alzheimer disease, tau protein

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Pathophysiology of Alzheimer Disease

10.2310/im.1335 ◽

2017 ◽

Author(s):

David Knopman

Keyword(s):

Cerebrospinal Fluid ◽

Alzheimer Disease ◽

Cortical Thickness ◽

Hippocampal Volume ◽

Csf Biomarkers ◽

Amyloid Pet ◽

Symptomatic Disease ◽

18F Fluorodeoxyglucose ◽

Β Amyloid ◽

Cortical Association Areas

Genetic discoveries coupled with neuropathologic investigations initially established the central role for β-amyloidosis in Alzheimer disease (AD). Three dominantly inherited genes (APP, PSEN1, and PSEN2) and one common allelic variant with lower penetrance (APOE) account for the majority of the genetic basis for AD. PET biomarkers for AD have been developed in the past decade and are fundamentally altering our view of the disease. The availability of PET tracers, first for amyloid and now for tau, has enabled researchers to develop a model of AD that begins long before people become symptomatic. In persons destined to develop dementia due to AD, brain β-amyloid levels begin to rise 10 to 20 years earlier. Other imaging changes that might precede symptomatic disease include (1) reductions in brain metabolic activity in a group of temporal and parietal cortical association areas that can be demonstrated by [18F]fluorodeoxyglucose-PET scanning; (2) losses of hippocampal volume as measured on structural magnetic resonance imaging; and (3) loss of cortical thickness or cortical volume in temporal and parietal cortical association areas. All of these changes are greatly accentuated once people become symptomatic. Although mild elevations in tau PET abnormalities can also be seen in presymptomatic individuals, it is only when persons become symptomatic that marked elevations in these abnormalities begin to occur in those same temporal and parietal cortical association areas. Cerebrospinal fluid (CSF) biomarkers provide a complementary view, with CSF β-amyloid levels falling (presumably due to aggregation within the cortex) even before amyloid PET abnormalities are visible. CSF total tau and phospho-tau levels begin to rise when persons are much closer to being symptomatic. The sum of these observations has allowed researchers to gain a far more insightful antemortem view of the pathophysiology of AD in humans than had previously been available from neuropathologic investigations. Keywords: β-amyloid, cerebrospinal fluid β-amyloid, cerebrospinal fluid phospho-tau, cortical thickness, [18F]fluorodeoxyglucose–positron emission tomography, hippocampal atrophy, preclinical Alzheimer disease, tau protein

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Validation of the LUMIPULSE automated immunoassay for the measurement of core AD biomarkers in cerebrospinal fluid

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2021-0651 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Johan Gobom ◽

Lucilla Parnetti ◽

Pedro Rosa-Neto ◽

Martin Vyhnalek ◽

Serge Gauthier ◽

...

Keyword(s):

Cerebrospinal Fluid ◽

Clinical Laboratory ◽

Amyloid Β ◽

Reference Method ◽

Diagnostic Tools ◽

Csf Biomarkers ◽

Meso Scale Discovery ◽

Total Tau ◽

Β Amyloid ◽

Automated Immunoassay

Abstract Objectives The core cerebrospinal fluid (CSF) biomarkers; total tau (tTau), phospho-tau (pTau), amyloid β 1-42 (Aβ 1-42), and the Aβ 1-42/Aβ 1-40 ratio have transformed Alzheimer’s disease (AD) research and are today increasingly used in clinical routine laboratories as diagnostic tools. Fully automated immunoassay instruments with ready-to-use assay kits and calibrators has simplified their analysis and improved reproducibility of measurements. We evaluated the analytical performance of the fully automated immunoassay instrument LUMIPULSE G (Fujirebio) for measurement of the four core AD CSF biomarkers and determined cutpoints for AD diagnosis. Methods Comparison of the LUMIPULSE G assays was performed with the established INNOTEST ELISAs (Fujirebio) for hTau Ag, pTau 181, β-amyloid 1-42, and with V-PLEX Plus Aβ Peptide Panel 1 (6E10) (Meso Scale Discovery) for Aβ 1-42/Aβ 1-40, as well as with a LC-MS reference method for Aβ 1-42. Intra- and inter-laboratory reproducibility was evaluated for all assays. Clinical cutpoints for Aβ 1-42, tTau, and pTau was determined by analysis of three cohorts of clinically diagnosed patients, comprising 651 CSF samples. For the Aβ 1-42/Aβ 1-40 ratio, the cutpoint was determined by mixture model analysis of 2,782 CSF samples. Results The LUMIPULSE G assays showed strong correlation to all other immunoassays (r>0.93 for all assays). The repeatability (intra-laboratory) CVs ranged between 2.0 and 5.6%, with the highest variation observed for β-amyloid 1-40. The reproducibility (inter-laboratory) CVs ranged between 2.1 and 6.5%, with the highest variation observed for β-amyloid 1-42. The clinical cutpoints for AD were determined to be 409 ng/L for total tau, 50.2 ng/L for pTau 181, 526 ng/L for β-amyloid 1-42, and 0.072 for the Aβ 1-42/Aβ 1-40 ratio. Conclusions Our results suggest that the LUMIPULSE G assays for the CSF AD biomarkers are fit for purpose in clinical laboratory practice. Further, they corroborate earlier presented reference limits for the biomarkers.

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