title: Naturally Occurring Autoantibodies against Tau Protein Are Reduced in Parkinson's Disease Dementia.
abstract: OBJECTIVE
  Altered levels of naturally occurring autoantibodies (nAbs) against disease-associated neuronal proteins have been reported for neurodegenerative diseases, such as Alzheimer's (AD) and Parkinson's disease (PD). Recent histopathologic studies suggest a contribution of both Lewy body- and AD-related pathology to Parkinson's disease dementia (PDD). Therefore, we explored nAbs against alpha-synuclein (αS), tau and β-amyloid (Aβ) in PDD compared to cognitively normal PD patients.
  
  
  METHODS
  We established three different ELISAs to quantify the nAbs-tau, nAbs-αS, and nAbs-Aβ levels and avidity towards their specific antigen in serum samples of 18 non-demented (PDND) and 18 demented PD patients (PDD), which were taken from an ongoing multi-center cohort study (DEMPARK/LANDSCAPE).
  
  
  RESULTS
  PDD patients had significantly decreased nAbs-tau serum levels compared to PDND patients (p = 0.007), whereas the serum titers of nAbs-αS and nAbs-Aβ were unchanged. For all three nAbs, no significant differences in avidity were found between PDD and PDND cohorts. However, within both patient groups, nAbs-tau showed lowest avidity to their antigen, followed by nAbs-αS, and nAbs-Aβ. Though, due to a high interassay coefficient of variability and the exclusion of many samples below the limit of detection, conclusions for nAbs-Aβ are only conditionally possible.
  
  
  CONCLUSIONS
  We detected a significantly decreased nAbs-tau serum level in PDD patients, indicating a potential linkage between nAbs-tau serum titer and cognitive deficits in PD. Thus, further investigation in larger samples is justified to confirm our findings.
authors: Department of Neurology, Philipps-University, Marburg, Germany.
authors: Yannick
authors: Y
authors: Kronimus
authors: Department of Neurology, Philipps-University, Marburg, Germany.
authors: Alexandra
authors: A
authors: Albus
authors: Department of Neurology, Philipps-University, Marburg, Germany.
authors: Monika
authors: M
authors: Balzer-Geldsetzer
authors: Department of Neurology, University of Ulm, Ulm, Germany.
authors: Sarah
authors: S
authors: Straub
authors: Department of Neurology, University of Ulm, Ulm, Germany.
authors: Elisa
authors: E
authors: Semler
authors: Department of Neurology, University of Ulm, Ulm, Germany.
authors: Markus
authors: M
authors: Otto
authors: German Rheumatism Research Centre Berlin, a Leibniz Institute, Berlin, Germany.|Charité University Medicine Berlin, Institute for Social Medicine, Epidemiology and Health Economics, Berlin, Germany.
authors: Jens
authors: J
authors: Klotsche
authors: Department of Neurology, Philipps-University, Marburg, Germany.|Department of Neuro-geriatrics, University Clinic, Essen, Germany.
authors: Richard
authors: R
authors: Dodel
authors: Department of Neurology, Philipps-University, Marburg, Germany.
authors: David
authors: D
authors: Mengel
mesh_terms: D016229:Amyloid beta-Peptides / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology*; D003072:Cognition Disorders / Q000276:immunology; D015331:Cohort Studies; D003704:Dementia / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D010300:Parkinson Disease / Q000276:immunology*; D051844:alpha-Synuclein / Q000276:immunology; D016875:tau Proteins / Q000276:immunology*
chemical_list: D016229:Amyloid beta-Peptides; D001323:Autoantibodies; D051844:alpha-Synuclein; D016875:tau Proteins