NEFL and Guillain-Barre syndrome: Johanna Gaiottino and his colleagues found that patients with AD, amyotrophic lateral sclerosis (ALS), and Guillain-Barré-syndrome (GBS) have higher levels of cerebrospinal fluid and serum NfL, and this change in NfL level is not accompanied by evidence of structural damage of central nervous system (CNS) [21].