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Diagnosing Alzheimer's disease (AD) poses significant challenges to health care, often resulting in delayed or inadequate patient care. The clinical integration of blood-based biomarkers (BBMs) for AD holds promise in enabling early detection of pathology and timely intervention. However, several critical considerations, such as the lack of consistent guidelines for assessing cognition, limited understanding of BBM test characteristics, insufficient evidence on BBM performance across diverse populations, and the ethical management of test results, must be addressed for widespread clinical implementation of BBMs in the United States. The Global CEO Initiative on Alzheimer's Disease BBM Workgroup convened to address these challenges and provide recommendations that underscore the importance of evidence-based guidelines, improved training for health-care professionals, patient empowerment through informed decision making, and the necessity of community-based studies to understand BBM performance in real-world populations. Multi-stakeholder engagement is essential to implement these recommendations and ensure credible guidance and education are accessible to all stakeholders., (© 2024 The Author(s). Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Blood-based biomarkers (BBM) for Alzheimer's disease (AD) are being increasingly used in clinical practice to support an AD diagnosis. In contrast to traditional diagnostic modalities, such as amyloid positron emission tomography and cerebrospinal fluid biomarkers, BBMs offer a more accessible and lower cost alternative for AD biomarker testing. Their unique scalability addresses the anticipated surge in demand for biomarker testing with the emergence of disease-modifying treatments (DMTs) that require confirmation of amyloid pathology. To facilitate the uptake of BBMs in clinical practice, The Global CEO Initiative on Alzheimer's Disease convened a BBM Workgroup to provide recommendations for two clinical implementational pathways for BBMs: one for current use for triaging and another for future use to confirm amyloid pathology. These pathways provide a standardized diagnostic approach with guidance on interpreting BBM test results. Integrating BBMs into clinical practice will simplify the diagnostic process and facilitate timely access to DMTs for eligible patients., (© 2024 The Author(s). Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Anti-amyloid treatments for early symptomatic Alzheimer disease have recently become clinically available in some countries, which has greatly increased the need for biomarker confirmation of amyloid pathology. Blood biomarker (BBM) tests for amyloid pathology are more acceptable, accessible and scalable than amyloid PET or cerebrospinal fluid (CSF) tests, but have highly variable levels of performance. The Global CEO Initiative on Alzheimer's Disease convened a BBM Workgroup to consider the minimum acceptable performance of BBM tests for clinical use. Amyloid PET status was identified as the reference standard. For use as a triaging test before subsequent confirmatory tests such as amyloid PET or CSF tests, the BBM Workgroup recommends that a BBM test has a sensitivity of ≥90% with a specificity of ≥85% in primary care and ≥75-85% in secondary care depending on the availability of follow-up testing. For use as a confirmatory test without follow-up tests, a BBM test should have performance equivalent to that of CSF tests - a sensitivity and specificity of ~90%. Importantly, the predictive values of all biomarker tests vary according to the pre-test probability of amyloid pathology and must be interpreted in the complete clinical context. Use of BBM tests that meet these performance standards could enable more people to receive an accurate and timely Alzheimer disease diagnosis and potentially benefit from new treatments., (© 2024. Springer Nature Limited.)

Background: Identifying individuals with mild cognitive impairment (MCI) who are likely to progress to Alzheimer's disease and related dementia disorders (ADRD) would facilitate the development of individualized prevention plans. We investigated the association between MCI and comorbidities of ADRD. We examined the predictive potential of these comorbidities for MCI risk determination using a machine learning algorithm., Methods: Using a retrospective matched case-control design, 5185 MCI and 15,555 non-MCI individuals aged ≥50 years were identified from MarketScan databases. Predictive models included ADRD comorbidities, age, and sex., Results: Associations between 25 ADRD comorbidities and MCI were significant but weakened with increasing age groups. The odds ratios (MCI vs non-MCI) in 50-64, 65-79, and ≥ 80 years, respectively, for depression (4.4, 3.1, 2.9) and stroke/transient ischemic attack (6.4, 3.0, 2.1). The predictive potential decreased with older age groups, with ROC-AUCs 0.75, 0.70, and 0.66 respectively. Certain comorbidities were age-specific predictors., Conclusions: The comorbidity burden of MCI relative to non-MCI is age-dependent. A model based on comorbidities alone predicted an MCI diagnosis with reasonable accuracy., (© 2023. The Author(s).)

Timely detection of the pathophysiological changes and cognitive impairment caused by Alzheimer's disease (AD) is increasingly pressing because of the advent of biomarker-guided targeted therapies that may be most effective when provided early in the disease. Currently, diagnosis and management of early AD are largely guided by clinical symptoms. FDA-approved neuroimaging and cerebrospinal fluid biomarkers can aid detection and diagnosis, but the clinical implementation of these testing modalities is limited because of availability, cost, and perceived invasiveness. Blood-based biomarkers (BBBMs) may enable earlier and faster diagnoses as well as aid in risk assessment, early detection, prognosis, and management. Herein, we review data on BBBMs that are closest to clinical implementation, particularly those based on measures of amyloid-β peptides and phosphorylated tau species. We discuss key parameters and considerations for the development and potential deployment of these BBBMs under different contexts of use and highlight challenges at the methodological, clinical, and regulatory levels., Competing Interests: Declaration of interests H.H. is an employee of Eisai and serves as reviewing editor for the journal Alzheimer’s & Dementia. H.H. is the inventor of 11 patents and has received no royalties for: In Vitro Multiparameter Determination Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders patent no. 8916388; In Vitro Procedure for Diagnosis and Early Diagnosis of Neurodegenerative Diseases patent no. 8298784; Neurodegenerative Markers for Psychiatric Conditions publication no. 20120196300; In Vitro Multiparameter Determination Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders publication no. 20100062463; In Vitro Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders publication no. 20100035286; In Vitro Procedure for Diagnosis and Early Diagnosis of Neurodegenerative Diseases publication no. 20090263822; In Vitro Method for The Diagnosis of Neurodegenerative Diseases patent no. 7547553; CSF Diagnostic in Vitro Method for Diagnosis of Dementias and Neuroinflammatory Diseases publication no. 20080206797; In Vitro Method for The Diagnosis of Neurodegenerative Diseases publication no. 20080199966; Neurodegenerative Markers for Psychiatric Conditions publication no. 20080131921; and Method for diagnosis of dementias and neuroinflammatory diseases based on an increased level of procalcitonin in cerebrospinal fluid: US patent no. 10921330. J.C. has provided consultation to Acadia, Actinogen, Alkahest, Alpha Cognition, AriBio, Biogen, BioVie, Cassava, Cerecin, Corium, Cortexyme, Diadem, EIP Pharma, Eisai, GemVax, Genentech, Green Valley, GAP Innovations, Grifols, Janssen, Karuna, Lilly, Lundbeck, LSP, Merck, NervGen, Novo Nordisk, Oligomerix, OptoCeutics, Ono, Otsuka, PRODEO, Prothena, reMYND, Resverlogix, Roche, Sage Therapeutics, Signant Health, Simcere, Sunbird Bio, Suven, TrueBinding, and Vaxxinity pharmaceutical, assessment, and investment companies. A.N. ha no personal conflicts to declare, but his employer NCGG shares some patents with Shimadzu and receives royalty. S.M. serves on the board of directors of Senscio Systems and the scientific advisory board of AiCure Technologies, ALZpath, and Boston Millennia Partners and has received consulting fees from Biogen, C(2)N, Eisai, Novartis, and Roche/Genentech. S.O. has multiple patents on precision medicine for neurodegenerative diseases and is the founding scientist of Cx Precision Medicine, Inc. L.M.S. has received compensation for teaching activities from Biogen. Y.H., M.C., and R.B. are employees of Eisai. A.V. declares no competing interests related to the present paper. A.V.’s contribution to this paper reflects entirely and exclusively his own academic expertise on the matter. A.V. was an employee of Eisai (November 2019–June 2021). A.V. has not received any fees or honoraria since November 2019. Before November 2019, A.V. received lecture honoraria from Roche, MagQu, and Servier. K.B. has served as a consultant and on advisory boards for Acumen, ALZPath, BioArctic, Biogen, Eisai, Lilly, Moleac Pte. Ltd, Novartis, Ono Pharma, Prothena, Roche Diagnostics, and Siemens Healthineers; has served on data monitoring committees for Julius Clinical and Novartis; has given lectures, produced educational materials, and participated in educational programs for AC Immune, Biogen, Celdara Medical, Eisai and Roche Diagnostics; and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the Gothenburg University Ventures Incubator Program. S.E.S. has analyzed data provided by C(2)N Diagnostics to Washington University and served on an advisory board for Eisai., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: Neurite orientation dispersion and density imaging (NODDI), a multi-compartment diffusion-weighted imaging (DWI) model, may be useful for detecting early cortical microstructural alterations in Alzheimer's disease prior to cognitive impairment., Methods: Using neuroimaging (NODDI and T1-weighted magnetic resonance imaging [MRI]) and cerebrospinal fluid (CSF) biomarker data (measured using Elecsys® CSF immunoassays) from 219 cognitively unimpaired participants, we tested the main and interactive effects of CSF amyloid beta (Aβ) 42 /Aβ 40 and phosphorylated tau (p-tau) on cortical NODDI metrics and cortical thickness, controlling for age, sex, and apolipoprotein E ε4., Results: We observed a significant CSF Aβ 42 /Aβ 40 × p-tau interaction on cortical neurite density index (NDI), but not orientation dispersion index or cortical thickness. The directionality of these interactive effects indicated: (1) among individuals with lower CSF p-tau, greater amyloid burden was associated with higher cortical NDI; and (2) individuals with greater amyloid and p-tau burden had lower cortical NDI, consistent with cortical neurodegenerative changes., Discussion: NDI is a particularly sensitive marker for early cortical changes that occur prior to gross atrophy or development of cognitive impairment., (© 2021 the Alzheimer's Association.)

The core cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers amyloid beta (Aβ42 and Aβ40), total tau, and phosphorylated tau, have been extensively clinically validated, with very high diagnostic performance for AD, including the early phases of the disease. However, between-center differences in pre-analytical procedures may contribute to variability in measurements across laboratories. To resolve this issue, a workgroup was led by the Alzheimer's Association with experts from both academia and industry. The aim of the group was to develop a simplified and standardized pre-analytical protocol for CSF collection and handling before analysis for routine clinical use, and ultimately to ensure high diagnostic performance and minimize patient misclassification rates. Widespread application of the protocol would help minimize variability in measurements, which would facilitate the implementation of unified cut-off levels across laboratories, and foster the use of CSF biomarkers in AD diagnostics for the benefit of the patients., (© 2021 Alzheimer's Association. Alzheimer's & Dementia published by Wiley Periodicals, LLC on behalf of Alzheimer's Association.)

Introduction: This study examines the utility of a multipanel of cerebrospinal fluid (CSF) biomarkers complementing Alzheimer's disease (AD) biomarkers in a clinical research sample. We compared biomarkers across groups defined by clinical diagnosis and pTau 181 /Aβ 42 status (+/-) and explored their value in predicting cognition., Methods: CSF biomarkers amyloid beta (Aβ) 42 , pTau 181 , tTau, Aβ 40 , neurogranin, neurofilament light (NfL), α-synuclein, glial fibrillary acidic protein (GFAP), chitinase-3-like protein 1 (YKL-40), soluble triggering receptor expressed on myeloid cells 2 (sTREM2), S100 calcium binding protein B (S100B), and interleukin 6 (IL6), were measured with the NeuroToolKit (NTK) for 720 adults ages 40 to 93 years (mean age = 63.9 years, standard deviation [SD] = 9.0; 50 with dementia; 54 with mild cognitive impairment [MCI], 616 unimpaired)., Results: Neurodegeneration and glial activation biomarkers were elevated in pTau 181 /Aβ 42 + MCI/dementia participants relative to all pTau 181 /Aβ 42 - participants. Neurodegeneration biomarkers increased with clinical severity among pTau 181 /Aβ 42 + participants and predicted worse cognitive performance. Glial activation biomarkers were unrelated to cognitive performance., Discussion: The NTK contains promising markers that improve the pathophysiological characterization of AD. Neurodegeneration biomarkers beyond tTau improved statistical prediction of cognition and disease stages., (© 2020 the Alzheimer's Association.)

Introduction: We examined the influence of common preanalytical factors on the measurement of Alzheimer's disease-specific biomarkers in human plasma., Methods: Amyloid β peptides (Aβ[1-40], Aβ[1-42]) and total Tau plasma concentrations were quantified using fully automated Roche Elecsys assays., Results: Aβ(1-40), Aβ(1-42), and total Tau plasma concentrations were not affected by up to three freeze/thaw cycles, up to five tube transfers, the collection tube material, or the size; circadian rhythm had a minor effect. All three biomarkers were influenced by the anticoagulant used, particularly total Tau. Aβ concentrations began decreasing 1 hour after blood draw/before centrifugation and decreased by up to 5% and 10% at 2 and 6 hours, respectively. For separated plasma, time to measurement influenced Aβ levels by up to 7% after 6 hours and 10% after 24 hours., Discussion: Our findings provide guidance for standardizing blood sample collection, handling, and storage to ensure reliable analysis of Alzheimer's disease plasma biomarkers in routine practice and clinical trials.

Alzheimer's disease (AD)-a complex disease showing multiple pathomechanistic alterations-is triggered by nonlinear dynamic interactions of genetic/epigenetic and environmental risk factors, which, ultimately, converge into a biologically heterogeneous disease. To tackle the burden of AD during early preclinical stages, accessible blood-based biomarkers are currently being developed. Specifically, next-generation clinical trials are expected to integrate positive and negative predictive blood-based biomarkers into study designs to evaluate, at the individual level, target druggability and potential drug resistance mechanisms. In this scenario, systems biology holds promise to accelerate validation and qualification for clinical trial contexts of use-including proof-of-mechanism, patient selection, assessment of treatment efficacy and safety rates, and prognostic evaluation. Albeit in their infancy, systems biology-based approaches are poised to identify relevant AD "signatures" through multifactorial and interindividual variability, allowing us to decipher disease pathophysiology and etiology. Hopefully, innovative biomarker-drug codevelopment strategies will be the road ahead towards effective disease-modifying drugs.
., (© 2019, AICH – Servier GroupCopyright © 2019 AICH – Servier Group. All rights reserved.)

Alzheimer's disease (AD) is a progressive neurodegenerative disease with a complex and heterogeneous pathophysiology. The number of people living with AD is predicted to increase; however, there are no disease-modifying therapies currently available and none have been successful in late-stage clinical trials. Fluid biomarkers measured in cerebrospinal fluid (CSF) or blood hold promise for enabling more effective drug development and establishing a more personalized medicine approach for AD diagnosis and treatment. Biomarkers used in drug development programmes should be qualified for a specific context of use (COU). These COUs include, but are not limited to, subject/patient selection, assessment of disease state and/or prognosis, assessment of mechanism of action, dose optimization, drug response monitoring, efficacy maximization, and toxicity/adverse reactions identification and minimization. The core AD CSF biomarkers Aβ42, t-tau, and p-tau are recognized by research guidelines for their diagnostic utility and are being considered for qualification for subject selection in clinical trials. However, there is a need to better understand their potential for other COUs, as well as identify additional fluid biomarkers reflecting other aspects of AD pathophysiology. Several novel fluid biomarkers have been proposed, but their role in AD pathology and their use as AD biomarkers have yet to be validated. In this review, we summarize some of the pathological mechanisms implicated in the sporadic AD and highlight the data for several established and novel fluid biomarkers (including BACE1, TREM2, YKL-40, IP-10, neurogranin, SNAP-25, synaptotagmin, α-synuclein, TDP-43, ferritin, VILIP-1, and NF-L) associated with each mechanism. We discuss the potential COUs for each biomarker.

Introduction: We studied whether fully automated Elecsys cerebrospinal fluid (CSF) immunoassay results were concordant with positron emission tomography (PET) and predicted clinical progression, even with cutoffs established in an independent cohort., Methods: Cutoffs for Elecsys amyloid-β 1-42 (Aβ), total tau/Aβ(1-42), and phosphorylated tau/Aβ(1-42) were defined against [ 18 F]flutemetamol PET in Swedish BioFINDER (n = 277) and validated against [ 18 F]florbetapir PET in Alzheimer's Disease Neuroimaging Initiative (n = 646). Clinical progression in patients with mild cognitive impairment (n = 619) was studied., Results: CSF total tau/Aβ(1-42) and phosphorylated tau/Aβ(1-42) ratios were highly concordant with PET classification in BioFINDER (overall percent agreement: 90%; area under the curve: 94%). The CSF biomarker statuses established by predefined cutoffs were highly concordant with PET classification in Alzheimer's Disease Neuroimaging Initiative (overall percent agreement: 89%-90%; area under the curves: 96%) and predicted greater 2-year clinical decline in patients with mild cognitive impairment. Strikingly, tau/Aβ ratios were as accurate as semiquantitative PET image assessment in predicting visual read-based outcomes., Discussion: Elecsys CSF biomarker assays may provide reliable alternatives to PET in Alzheimer's disease diagnosis., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Biomarker discovery and development for clinical research, diagnostics and therapy monitoring in clinical trials have advanced rapidly in key areas of medicine - most notably, oncology and cardiovascular diseases - allowing rapid early detection and supporting the evolution of biomarker-guided, precision-medicine-based targeted therapies. In Alzheimer disease (AD), breakthroughs in biomarker identification and validation include cerebrospinal fluid and PET markers of amyloid-β and tau proteins, which are highly accurate in detecting the presence of AD-associated pathophysiological and neuropathological changes. However, the high cost, insufficient accessibility and/or invasiveness of these assays limit their use as viable first-line tools for detecting patterns of pathophysiology. Therefore, a multistage, tiered approach is needed, prioritizing development of an initial screen to exclude from these tests the high numbers of people with cognitive deficits who do not demonstrate evidence of underlying AD pathophysiology. This Review summarizes the efforts of an international working group that aimed to survey the current landscape of blood-based AD biomarkers and outlines operational steps for an effective academic-industry co-development pathway from identification and assay development to validation for clinical use.

Introduction: Cerebrospinal fluid (CSF) biomarkers have the potential to improve the diagnostic accuracy of Alzheimer's disease, yet there is a lack of harmonized preanalytical CSF handling protocols., Methods: This systematic review summarizes the current literature on the influence of preanalytical variables on CSF biomarker concentration. We evaluated the evidence for three core CSF biomarkers: β-amyloid 42, total tau, and phosphorylated tau., Results: The clinically important variables with the largest amount of conflicting data included the temperature at which samples are stored, the time nonfrozen samples can be stored, and possible effects of additives such as detergents, blood contamination, and centrifugation. Conversely, we discovered that there is consensus that tube material has a significant effect., Discussion: A unified CSF handling protocol is recommended to reduce preanalytical variability and facilitate comparison of CSF biomarkers across studies and laboratories. In future, experiments should use a gold standard with fresh CSF collected in low binding tubes., (Copyright © 2018 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.)

Parkinson's disease biomarkers are needed to increase diagnostic accuracy, to objectively monitor disease progression and to assess therapeutic efficacy as well as target engagement when evaluating novel drug and therapeutic strategies. This article summarizes perianalytical considerations for biomarker studies (based on immunoassays) in Parkinson's disease, with emphasis on quantifying total α-synuclein protein in biological fluids. Current knowledge and pitfalls are discussed, and selected perianalytical variables are presented systematically, including different temperature of sample collection and types of collection tubes, gradient sampling, the addition of detergent, aliquot volume, the freezing time, and the different thawing methods. We also discuss analytical confounders. We identify gaps in the knowledge and delineate specific areas that require further investigation, such as the need to identify posttranslational modifications of α-synuclein and antibody-independent reference methods for quantification, as well as the analysis of potential confounders, such as comorbidities, medication, and phenotypes of Parkinson's disease in larger cohorts. This review could be used as a guideline for future Parkinson's disease biomarker studies and will require regular updating as more information arises in this growing field, including new technical developments as they become available. In addition to reviewing best practices, we also identify the current technical limitations and gaps in the knowledge that should be addressed to enable accurate and quantitative assessment of α-synuclein levels in the clinical setting. © 2017 International Parkinson and Movement Disorder Society., (© 2017 International Parkinson and Movement Disorder Society.)

The diversity of the hepatitis B surface antigen (HBsAg) has a significant impact on the performance of diagnostic screening tests and the clinical outcome of hepatitis B infection. Neutralizing or diagnostic antibodies against the HBsAg are directed towards its highly conserved major hydrophilic region (MHR), in particular towards its "a" determinant subdomain. Here, we explored, on a global scale, the genetic diversity of the HBsAg MHR in a large, multi-ethnic cohort of randomly selected subjects with HBV infection from four continents. A total of 1553 HBsAg positive blood samples of subjects originating from 20 different countries across Africa, America, Asia and central Europe were characterized for amino acid variation in the MHR. Using highly sensitive ultra-deep sequencing, we found 72.8% of the successfully sequenced subjects (n = 1391) demonstrated amino acid sequence variation in the HBsAg MHR. This indicates that the global variation frequency in the HBsAg MHR is threefold higher than previously reported. The majority of the amino acid mutations were found in the HBV genotypes B (28.9%) and C (25.4%). Collectively, we identified 345 distinct amino acid mutations in the MHR. Among these, we report 62 previously unknown mutations, which extends the worldwide pool of currently known HBsAg MHR mutations by 22%. Importantly, topological analysis identified the "a" determinant upstream flanking region as the structurally most diverse subdomain of the HBsAg MHR. The highest prevalence of "a" determinant region mutations was observed in subjects from Asia, followed by the African, American and European cohorts, respectively. Finally, we found that more than half (59.3%) of all HBV subjects investigated carried multiple MHR mutations. Together, this worldwide ultra-deep sequencing based genotyping study reveals that the global prevalence and structural complexity of variation in the hepatitis B surface antigen have, to date, been significantly underappreciated.

Background & Aims: Noninvasive techniques are needed to assess hepatic fibrosis in patients with chronic hepatitis B. We developed a scoring system to determine the degree of fibrosis in patients with genotype B or genotype C hepatitis B virus (HBV) infection and positive for the hepatitis B e antigen., Methods: We performed a retrospective study to identify baseline variables associated with the severity of fibrosis (METAVIR scores, F0-F4) in a large phase 3 clinical trial of predominantly Asian patients (n = 710), using multivariate logistic regression analyses. Significant variables were used to construct predictive models using optimal cut-off values. The final model was validated in similar patients from a large phase 4 clinical trial (n = 465)., Results: We developed 2 prediction scoring systems (PSs). PS1 analyzed data on HBV genotype (B vs. C), patient age (<30 vs. ≥30 y), level of hepatitis B surface antigen (≤17,500 vs. >17,500 IU/mL), and level of alanine aminotransferase (≤3-fold vs. >3-fold the upper limit of normal). PS2 analyzed data on only age and level of hepatitis B surface antigen. PS1 identified patients with F0 to F1 vs. F2 to F4 fibrosis with more than 87% specificity and a positive predictive value greater than 75; it identified patients with F0 to F2 vs. F2 to F4 fibrosis with approximately 95% specificity and a positive predictive value (PPV) of approximately 97%. PS2 identified patients with F0 to F1 fibrosis with less accuracy than PS1, but identified patients with F0 to F2 fibrosis with an almost identical level of sensitivity and PPV., Conclusions: We developed a simple scoring system to determine the severity of fibrosis in patients with genotypes B or C HBV infection who are hepatitis B e antigen positive. Our system differentiated patients with no or mild fibrosis (F0-F1) from those with marked or severe (F2-F4) fibrosis with a high PPV. The high level of specificity for the identification of nonsevere fibrosis (F0-F2) limits the risk of overlooking patients with severe fibrosis (F3-F4)., (Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Personalized health care (PHC) is an evolving field of medicine aimed at providing the right therapy to the right patient at the right time. This approach often incorporates the use of companion diagnostics (CDx) assays that provide information essential for the safe and effective use of the corresponding drug. In addition to oncology, many other therapy areas, such as cardiovascular, neurological, and infectious and inflammatory diseases, may benefit from PHC, owing to disease complexity and heterogeneity. Furthermore, although most U.S. Food and Drug Administration-approved CDx are based on molecular-based technologies, immunoassays can provide a significant contribution to the evolution of CDx in patient management. In this review we discuss how the incorporation of biomarker immunoassays into routine diagnostic testing may allow early and definitive detection of Alzheimer's disease and enable population enrichment in clinical trials. In addition, we will describe how biomarker-based CDx immunoassays have potential utility for stratifying patients with asthma based on their potential response to therapy and for selecting treatment according to phenotypic profile. Continued research into the underlying disease pathology and development of accurate and reliable diagnostic assays may ensure that PHC becomes the future standard for many indications., (© 2015 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.)

The ultimate goal of diagnostic testing is to guide disease management in order to improve patient outcomes and patient well-being. Patient populations are rarely homogenous and accurate diagnostic tests can dissect the patient population and identify those patients with similar symptoms but very different underlying pathophysiology that will respond differently to different treatments. This stratification of patients can direct patients to appropriate treatment and is likely to result in clinical benefits for patients and economic benefits for the healthcare system. In this article we look at the clinical and economic benefits afforded by clinical laboratory diagnostics in three disease areas that represent substantial clinical and healthcare burdens to society; heart failure, Alzheimer's disease and asthma.

Background & Aims: Little is currently known about the association between serum HBsAg or HBV DNA levels and the severity of liver disease in chronic hepatitis B (CHB) patients. Therefore, we investigated these relationships in a large cohort of unselected, well-characterized, treatment-naïve CHB patients., Methods: CHB patients were assessed at the Hôpital Beaujon in Paris, France, between 2000 and 2008. Serum samples and liver biopsies were obtained on the same day. HBsAg, HBV DNA, and HBV genotype were investigated using commercial diagnostic assays and liver histology was scored using the METAVIR system., Results: 406 patients were included in this cross-sectional study. Serum HBsAg and HBV DNA levels in hepatitis B e antigen-positive (HBeAg[+]) patients showed strong correlation (r=0.44, p<0.0001), as did serum HBsAg levels and fibrosis severity (r=0.43, p<0.0001). HBeAg(+) patients with moderate to severe fibrosis exhibited significantly lower serum HBsAg and HBV DNA levels compared with patients with no or mild fibrosis. Modeling analysis suggested a serum HBsAg cut-off of 3.85 logIU/ml would provide a theoretical sensitivity of 100% (95% CI: 0-100), theoretical specificity of 86% (95% CI: 50-100), and a negative predictive value of 100% (95% CI: 67-100) in HBeAg(+) patients infected with HBV genotype B or C., Conclusions: We found an association between low serum HBsAg levels and moderate to severe fibrosis in HBeAg(+) CHB patients. Furthermore, we described a serum HBsAg cut-off for the prediction of fibrosis severity in CHB patients infected with HBV genotype B or C., (Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Unlabelled: We investigated the relationship between hepatitis B virus surface antigen (HBsAg) serum level decline and posttreatment response in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B from a large multinational study of pegylated interferon alfa-2a (peginterferon alfa-2a), with or without lamivudine, versus lamivudine alone. Serum HBsAg was quantified using the Architect assay (Abbott Diagnostics) at pretreatment, end of treatment (week 48), and 6 months after the end of treatment (week 72) in sera from 386 of the 537 patients who participated in the multinational study (peginterferon alfa-2a, 127; peginterferon alfa-2a plus lamivudine, 137; lamivudine monotherapy, 122). Pretreatment HBsAg levels varied according to genotype, with the highest levels present in patients infected with genotypes A (median, 4.11 log(10) IU/mL) and D (median, 3.85 log(10) IU/mL). Significant on-treatment decline in HBsAg was observed during treatment with peginterferon alfa-2a (alone or combined with lamivudine; mean decline at week 48, -0.71 and -0.67 log(10) IU/mL, respectively, P < 0.001), but not during treatment with lamivudine alone (-0.02 log(10) IU/mL). Significantly more patients treated with peginterferon alfa-2a (21%) or peginterferon alfa-2a plus lamivudine (17%) achieved HBsAg levels <100 IU/mL at the end of treatment compared with lamivudine (1%) (both P < 0.001 versus lamivudine). End-of-treatment HBsAg level correlated strongly with HBV DNA suppression to 1 log(10) IU/mL were significantly associated with sustained HBsAg clearance 3 years after treatment (both P < 0.0001)., Conclusion: On-treatment quantification of HBsAg in patients with HBeAg-negative chronic hepatitis B treated with peginterferon alfa-2a may help identify those likely to be cured by this therapy and optimize treatment strategies.

The interaction of CD40 expressed by immunocompetent cells with its ligand CD154 on the surface of T-helper cells plays a crucial role in the immune response. Recently, the presence of CD40 was also demonstrated on a variety of carcinomas. Whereas the critical relevance of CD40 in cytotoxic T-cell priming via dendritic cells is already established, the biological role of CD40/CD154 interactions in nonhematopoetic cells is still unclear. In the present study we demonstrate that CD154 expression density is down-regulated on activated T cells on interaction with CD40+ tumor cells. Naive T cells cocultured with CD40+carcinoma showed impaired functionality as indicated by a reduced frequency of IFN-gamma secreting cells, reduced interleukin 2 secretion, impaired proliferation, and a lack of CD154 re-expression on restimulation. In distinction, T-cell effector lysing capacity was not impaired by CD40-expressing tumor cell targets. The present results suggest that in marked contrast to antigen-presenting cells, CD40 expression on carcinoma cells suppresses T-cell activation. Our findings support the statement that CD40 functions are context dependent and imply a new function for CD40 expressed on nonantigen-presenting cells.

One possible reason for the poor immunogenicity of tumors is the induction of peripheral tolerance by tumor cells that fail to deliver costimulatory signals. Furthermore, T cells stimulated with wild-type tumor cells often fail to secrete cytokines. The present study has been undertaken to identify cytokines that cooperate with CD80 in T-cell activation in vitro toward human breast and ovarian carcinoma cell lines. Tumor cell-mediated T-lymphocyte activation was analyzed directly in allogeneic mixed lymphocyte/tumor cell cultures as proliferation and effector functions were assessed in cytotoxic T-cell assays. Interleukin-7 (IL-7) amplified the proliferative response toward CD80-transfected breast and ovarian carcinomas and stimulated predominantly CD4+ T lymphocytes. IL-12 represses the proliferative response of naive T cells but cooperates with CD80-mediated activation during secondary stimulations. In long-term T-cell cultures, IL-12 synergizes with CD80 expression to stimulate cytolytic CD8+ T-cell lines, which recognize a breast carcinoma line in a human histocompatibility leukocyte antigen-restricted manner. These studies illustrate that costimulation is necessary for tumor cells to function as alloantigen-presenting cells. Furthermore, when added after the priming of T cells with CD80-transfected tumor cells, IL-12 could be helpful in propagating sufficient T-cell numbers to be used in adoptive transfers during cellular immunotherapy.

Allogeneic human histocompatibility leukocyte antigen (HLA)-matched tumor cell lines that have been made immunogenic by the transfer of genes encoding for costimulatory molecules such as CD80 are considered to be potential vaccines for the induction of systemic immune reactions in cancer patients. We used a human HLA-A2.1+ CD80-transfected breast carcinoma cell line (KS-CD80) and investigated in vitro the efficiency at which antigen (Ag)-specific responses were induced following the stimulation of allogeneic HLA-A2.1-matched T lymphocytes. The influenza matrix protein M1 was used as a model Ag. It was either endogenously expressed or exogenously loaded as a peptide (matrix protein), and the frequency of the generated specific T cells was determined. The expression of CD80 in KS cells was required for an effective activation and expansion of Ag-specific T cells. This response was augmented following the pretreatment of KS-CD80 cells with interferon-gamma and tumor necrosis factor-alpha. Interleukin-4 (IL-4), IL-7, and IL-12 further increased T-cell expansion. IL-7 was best at supporting the generation of T cells with Ag specificity. This investigation demonstrates that allogeneic CD80+ tumor cells can induce Ag-specific, HLA-restricted T lymphocytes at a high frequency. Our study supports the use of allogeneic cell lines for the induction of specific T-cell responses in tumor patients.

At cellular surfaces, urokinase-type plasminogen activator (uPA) is bound to a specific receptor (uPA-R). When bound to this receptor, uPA activates plasminogen, which is derived from plasma or the interstitial fluids. Thus, plasmin is provided for proteolysis of pericellular proteinaceous substrates. Here we demonstrate by immunocytology and laser scan microscopy that in the human keratinocyte cell line HaCaT uPA-R and uPA are localized together with the integrin alpha v beta 5 in focal contacts. Via the integrin alpha v beta 5, HaCaT cells adhere to vitronectin in a RGD-dependent manner. Plasmin interfered with the alpha v beta 5-mediated keratinocyte adhesion to vitronectin, most likely via cleavage of vitronectin and destruction of its cell binding function. Our findings demonstrate that plasmin, when generated by the uPA-dependent cell surface-associated pathway of plasminogen activation, can abrogate the cell-binding function of vitronectin and can thus disturb the adhesive interaction with this matrix molecule. In focal contacts molecules are assembled that are crucial for adhesion to vitronectin (i.e., the integrin alpha v beta 5), as well as for the generation of plasmin (i.e., uPA-R and uPA), which can negatively influence the binding interaction. We suggest that the plasmin-mediated abrogation of the interaction between the integrin alpha v beta 5 and vitronectin is a pathway of negative regulation; the codistribution of uPA-R/uPA and alpha v beta 5 in focal contacts may restrict this process to areas of cell/matrix contact.

Plasmin is thought to be involved in the pericellular proteolysis of the human epidermis under physiological and pathological conditions. Plasmin is provided by activation of the proenzyme plasminogen. We have explored in vitro whether plasminogen is bound and activated at the keratinocyte surface, a possible mechanism for providing plasmin in the pericellular space. Plasminogen and plasmin could be eluted from the surface of keratinocytes grown in serum-containing medium. When plasminogen was added to cultured keratinocytes it was activated by cell-associated urokinase-type plasminogen activator. The activation required plasminogen binding to the cell surface. Plasminogen binding by keratinocytes was saturable and proceeded in a time- and concentration-dependent manner. Surface-bound plasmin was rapidly displaced from the surface into the culture supernatant. When compared to plasmin in solution surface-bound plasmin was relatively protected from interaction with the specific inhibitor alpha 2-antiplasmin. Addition of exogenous plasmin or plasmin generation by the keratinocyte-associated plasminogen activators was ensued by the detachment of adherent keratinocytes in culture. Along the same line, plasmin counteracted keratinocyte adhesion to fibrin-coated but not to collagen-coated culture plates. The findings indicate that plasmin may be generated in the pericellular space of keratinocytes and may interfere with the adhesion to particular extracellular substrates.