Only two patients had an intense elevation of tested biomarkers of neuronal death, an HTLV-1 AC (Patient 5C) and a 61-year-old woman (Patient 5B) with early HAM/TSP onset (14 months) and mild disability, which showed high levels of tTau (490.5 pg/mL), NfL (1,738 pg/mL), pNfH (1,222 pg/mL). Here, NEFL is linked to tropical spastic paraparesis.