title: Plasma neurofilament light chain predicts progression in progressive supranuclear palsy.
abstract: Blood-based biomarkers for neurodegenerative conditions could improve diagnosis and treatment development. Neurofilament light chain (NfL), a marker of axonal injury, is elevated in cerebrospinal fluid (CSF) of patients with progressive supranuclear palsy (PSP). The goal of this study was to determine the diagnostic and prognostic value of plasma NfL in patients with PSP.
  
  
  
  Plasma NfL was measured with ultrasensitive digital immunoassay-based technology at baseline and 1-year follow-up in a pilot cohort of 15 PSP patients and 12 healthy controls, and a validation cohort of 147 PSP patients. Mixed linear models tested the ability of plasma NfL to predict neurological, cognitive and functional decline, and brain atrophy.
  
  
  
  Baseline mean plasma NfL levels were elevated in PSP patients (31 ± 4 pg/mL, vs. control, 17.5 ± 1 pg/mL, P < 0.05) and this difference persisted at follow-up. A cutoff value of 20 pg/mL related to the diagnosis of PSP with a sensitivity of 0.80 and specificity of 0.83 (positive likelihood ratio = 4.7 and a negative likelihood radio of 0.24). Patients with higher NfL levels had more severe neurological (PSPRS, -36.9% vs. -28.9%, P = 0.04), functional (SEADL, -38.2% vs. -20%, P = 0.03), and neuropsychological (RBANS, -23.9% vs. -12.3%, P = 001) deterioration over 1 year. Higher baseline NfL predicted greater whole-brain and superior cerebellar peduncle volume loss. Plasma and CSF NfL were significantly correlated (r = 0.74, P = 0.002).
  
  
  
  Plasma NfL is elevated in PSP and could be of value as a biomarker both to assist clinical diagnosis and to monitor pharmacodynamic effects on the neurodegenerative process in clinical trials.
authors.affiliation: Memory and Aging Center Department of Neurology University of California, San Francisco San Francisco California.
authors.forename: Julio C
authors.initials: JC
authors.lastname: Rojas
authors.affiliation: Memory and Aging Center Department of Neurology University of California, San Francisco San Francisco California.
authors.forename: Anna
authors.initials: A
authors.lastname: Karydas
authors.affiliation: Memory and Aging Center Department of Neurology University of California, San Francisco San Francisco California.
authors.forename: Jee
authors.initials: J
authors.lastname: Bang
authors.affiliation: Memory and Aging Center Department of Neurology University of California, San Francisco San Francisco California.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Tsai
authors.affiliation: Clinical Neurochemistry Laboratory Institute of Neuroscience and Physiology Sahlgrenska Academy at University of Gothenburg Sahlgrenska University Hospital Mölndal Sweden.
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
authors.affiliation: Clinical Neurochemistry Laboratory Institute of Neuroscience and Physiology Sahlgrenska Academy at University of Gothenburg Sahlgrenska University Hospital Mölndal Sweden.
authors.forename: Victor
authors.initials: V
authors.lastname: Liman
authors.affiliation: Memory and Aging Center Department of Neurology University of California, San Francisco San Francisco California.
authors.forename: Joel H
authors.initials: JH
authors.lastname: Kramer
authors.affiliation: Memory and Aging Center Department of Neurology University of California, San Francisco San Francisco California.
authors.forename: Howard
authors.initials: H
authors.lastname: Rosen
authors.affiliation: Memory and Aging Center Department of Neurology University of California, San Francisco San Francisco California.
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Miller
authors.affiliation: Clinical Neurochemistry Laboratory Institute of Neuroscience and Physiology Sahlgrenska Academy at University of Gothenburg Sahlgrenska University Hospital Mölndal Sweden; Department of Molecular Neuroscience UCL Institute of Neurology Queen Square London United Kingdom.
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.affiliation: Memory and Aging Center Department of Neurology University of California, San Francisco San Francisco California.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Boxer