Cerebrospinal fluid and serum antibodies against neurofilaments in patients with amyotrophic lateral sclerosis

Background: The aim of the study was to assess autoimmune involvement in amyotrophic lateral sclerosis (ALS). Methods: We measured IgG antibodies against light (NFL) and medium (NFM) subunits of neurofilaments using ELISA in paired cerebrospinal fluid (CSF) and serum samples from 38 ALS patients and 20 controls. Results: Serum levels of anti-NFL were higher in ALS patients than in controls (P < 0.005). Serum anti-NFL antibodies and intrathecal anti-NFM antibodies were related to patient disability (serum anti-NFL: P < 0.05; intrathecal anti-NFM: P < 0.05). Anti-NFL levels were significantly correlated with anti-NFM levels in ALS (P < 0.001) and the control group (P < 0.0001) in the CSF, but not in serum. Anti-NFL and anti-NFM antibodies significantly correlated between serum and CSF in the ALS group (anti-NFL: P < 0.0001; anti-NFM: P < 0.001) and in the control group (anti-NFL: P < 0.05; anti-NFM: P < 0.05). Conclusions: Autoimmune humoral response to neurocytoskeletal proteins is associated with ALS.