Phosphorylated neurofilament heavy subunits as a marker of neurodegeneration in demyelinating diseases of the CNS

Neurofilaments are used as biomarkers of neurodegeneration, i.e., neuroinflammatory destruction of neurons, in various diseases of the nervous system. The purpose of our study is to clarify data on the pathogenesis and clinical prognosis of chronic and rare monophase demyelinating diseases. The content of phosphorylated neurofilament heavy subunits (pNFH) was measured in the cerebrospinal fluid (CSF) and blood serum using ELISA. The following groups of patients were studied: remittent multiple sclerosis (RMS, n = 56), secondary progressive multiple sclerosis (SPMS, n = 20), acute disseminated encephalomyelitis (ADEM, n = 7), neuromyelitis optica (NMO, n = 5), amyotrophic lateral sclerosis (ALS, n = 26), and the control group (n = 26). We found significant differences in the content of pNFH in the CSF between the RMS, ADEM, ALS groups and the control group; however, we did not observe any differences between the RMS, ADEM, and ALS groups per se. We did not find any differences in the contents of pNFH in the blood serum or any correlations of the pNFH levels with clinical features of diseases in these groups of patients. Based on this index, we conclude that neurodegeneration occurs in RMS, ADEM, and ALS. The pNFH content should be studied in larger cohorts of patients and at strictly defined time points.