Elevated NFL levels are found in CSF of PWH when this structural component is released during neuronal and axonal injury, which has been reported in several neurological disorders including HAND (Abdulle et al., 2007; Jessen Krut et al., 2014; Peterson et al., 2014; McGuire et al., 2015; Gisslén et al., 2016; Yilmaz et al., 2017). Here, NEFL is linked to nervous system disorder.