Description:
<jats:title>Abstract</jats:title><jats:p>The rarity of primary angiitis of the central nervous system (<jats:styled-content style="fixed-case">PACNS</jats:styled-content>) demands diagnostic and prognostic biomarkers. We retrospectively measured Neurofilament light chain (<jats:styled-content style="fixed-case">NFL</jats:styled-content>) concentrations in cerebrospinal fluid in a severely relapsing <jats:styled-content style="fixed-case">PACNS</jats:styled-content> patient at multiple time points during the course of the disease. A marked increase in <jats:styled-content style="fixed-case">NFL</jats:styled-content> levels preceding the onset of neuro‐axonal damage and arterial‐vessel abnormalities was observed with magnetic resonance imaging as well as with <jats:styled-content style="fixed-case">MR</jats:styled-content>‐ and conventional angiography. Thus, marked elevation of <jats:styled-content style="fixed-case">NFL</jats:styled-content> in <jats:styled-content style="fixed-case">PACNS</jats:styled-content> seems to occur ahead of definitive radiological abnormalities and might serve as a diagnostic biomarker.</jats:p>