Amyloid and Tau Protein Concentrations in Children with Meningitis and Encephalitis

Alzheimer’s disease (AD) has emerged as a growing threat to human health. It is a multifactorial disorder, in which abnormal amyloid beta metabolism and neuroinflammation have been demonstrated to play a key role. Intrathecal inflammation can be triggered by infections and precede brain damage for years. We analyzed the influence of infections of the central nervous system on biomarkers that are crucially involved in AD pathology. Analyses of the cerebrospinal fluid (CSF) levels of Aβ1–42, Aβ1–40, Tau, and pTau proteins were performed in 53 children with neuroinfections of viral (n = 26) and bacterial origin (n = 19), and in controls (n = 8). We found no changes in CSF amyloid Aβ1–42 concentrations, regardless of etiology. We showed an increase in tau and phosphorylated tau concentrations in purulent CNS infections of the brain, compared to other etiologies. Moreover, the total concentrations of tau in the CSF correlated with the CSF absolute number of neutrophils. These findings and the Aβ 42/40 concentration quotient discrepancies in CFS between meningitis and encephalitis suggest that infections may affect the metabolism of AD biomarkers

International initiative for harmonization of cerebrospinal fluid diagnostic comments in Alzheimer's disease

AbstractBackgroundThe quantification of cerebrospinal fluid (CSF) biomarkers (Abeta peptides [Ab1‐40 and Ab1‐42], tau protein and its phosphorylated form phospho‐tau) is progressively implemented in laboratories as an aid for the multidisciplinary diagnosis of Alzheimer disease (AD), DeKosky ST, Alz dementia, 2011, PMID: 21322828 . However, no consensus has been defined among the different laboratories involved to adapt the conclusions/comments to the level of quantified CSF biomarkers. As a result, although the analytical methods for such quantification may be similar across the laboratories involved in this clinical task, the conclusions transmitted to the physician in charge (neurologist or psychiatrist) may be quite different. Harmonization of this report is thus necessary so patients' care and research stratification can be similar wherever the analysis is performed.MethodA total of 34 laboratories (involved in CSF biomarkers measurement) across the world accepted to be part of our project of diagnostic's comments harmonization (represented countries: Austria, Belgium, Canada, France, Germany, Italy, Netherland, Poland, Spain, Sweden, United Kingdom, USA). As a first step, we defined the 9 most typical biochemical profiles, according to the level of CSF biomarkers and their combination. For each profile, each laboratory was asked to provide us with the comments/conclusions given in routine clinical practice. We then collected and pooled all the comments in a common file, so that the laboratories could, as a second step, choose and order three of these comments (for each biochemical profile defined), according to their reliability in clinical practice.ResultWe are currently analysing the second step‐answers of the laboratories, in order to define a consensual pattern of comments and conclusions that could be implemented in all the laboratories involved in the biochemical diagnosis of AD. Obtained data will be presented.ConclusionThe discrepancies of the comments for AD biochemical diagnosis across laboratories worldwide can be confusing and it is of strong importance to harmonize them (according to the level of quantified biomarkers and other information likely available such as the age, APOE genotype...). Our initiative will likely provide such harmonized pattern of comments/conclusions, thus ensuring equal care of patients across the different diagnostic centres

Clinical reporting following the quantification of cerebrospinal fluid biomarkers in Alzheimer's disease: An international overview

International audienceIntroduction: The current practice of quantifying cerebrospinal fluid (CSF) biomarkers as an aid in the diagnosis of Alzheimer's disease (AD) varies from center to center. For a same biochemical profile, interpretation and reporting of results may differ, which can lead to misunderstandings and raises questions about the commutability of tests.Methods: We obtained a description of (pre-)analytical protocols and sample reports from 40 centers worldwide. A consensus approach allowed us to propose harmonized comments corresponding to the different CSF biomarker profiles observed in patients.Results: The (pre-)analytical procedures were similar between centers. There was considerable heterogeneity in cutoff definitions and report comments. We therefore identified and selected by consensus the most accurate and informative comments regarding the interpretation of CSF biomarkers in the context of AD diagnosis.Discussion: This is the first time that harmonized reports are proposed across worldwide specialized laboratories involved in the biochemical diagnosis of AD