NEFL and dementia: Circulating levels of plasma biomarkers GFAP and NFL have previously been shown to reflect AD-related neuropathology.53 A study by You et al.54 conducted proteomic profiling on approximately 52,000 plasma samples from the UK biobank and found that proteins GFAP and NFL were consistently associated with all all-cause dementia, Alzheimer's disease and vascular dementia.