NEFL and variant Creutzfeldt-Jakob disease: Compared with the AD group, plasma NfL was higher in all prion disease types: sCJD (z = 9.1, p < 0.0001), symptomatic IPD (z = 3.5, p = 0.0062), vCJD (z = 3.0, p = 0.037) and iatrogenic CJD (z = 4.9, p < 0.0001).