Serum and cerebrospinal fluid heavy neurofilaments and antibodies against them in early multiple sclerosis

• Antibodies to heavy neurofilaments (NFH) were increased in early multiple sclerosis.
• CSF/serum ratio of anti-NFH antibodies was increased in early multiple sclerosis.
• Changes associated with NFH were more pronounced for antibodies than for protein.

Heavy neurofilaments (NFH) released from neurons during axonal injury induce a humoral immune response. We measured CSF and serum levels of NFH proteins and anti-NFH IgG antibodies in 19 patients with clinically isolated syndrome (CIS) converting to multiple sclerosis, in 20 stable CIS patients, 23 patients with multiple sclerosis (MS) and 32 control subjects using ELISA. CSF and intrathecal levels and CSF/serum ratios of anti-NFH antibodies were increased in the CIS patients early developing MS while NFH protein concentrations were similar among the groups. Changes associated with NFH are more pronounced for antibodies than for protein itself and may aid in prediction of CIS patients.