nEVs containing the neurotoxic proteins amyloid beta (Aβ), neurofilament light (NFL), p-T181-tau, and/or the inflammatory protein HMGB1 have been isolated from individuals with HIV cognitive impairment [20,21], Alzheimer’s disease (AD) [22], and traumatic brain injury (TBI) [23,24,25]. Here, NEFL is linked to early-onset autosomal dominant Alzheimer disease.