In conclusion, NFL is a sensitive biomarker for axonal injury in several neurological disorders including HAND (Abdulle et al., 2007; Gisslén et al., 2007, 2016; Yilmaz et al., 2017), and the correlation found between CSF NFL and neopterin in NCI subjects suggests an association between NCI, CNS inflammation, and neuronal damage (Edén et al., 2016). Here, NEFL is linked to nervous system disorder.