Cerebrospinal Fluid Phosphorylated Neurofilament Subunit NF-H (pNF-H) is a Specific Biomarker and Its Pattern is Predictive for Spinal Cord Injury

Abstract

Introduction In this study, we measured the phosphorylated neurofilament subunit NF-H (pNF-H) in the cerebrospinal fluid (CSF) of patients with spinal cord injury (SCI) and we set the correlation between the pNF-H levels and the severity of the injury. Patients and Methods The study included 20 patients with acute traumatic SCI: 12 patients with complete SCI and 8 patients with incomplete SCI. All patients were classified according to the American Spinal Injury Association Impairment Scale and all patients underwent surgery during the first 24 hours (decompression, stabilization). We measured daily the heavy phosphorylated neurofilament subunit (pNF-H) concentration by sandwich ELISA test in CSF of all patients and we correlated the values of pNF-H with the clinical evolution. Results For all patients with SCI, pNF-H was detectable in CSF samples and the values were different in the cases of complete SCI compared with the cases of incomplete SCI and the cerebrospinal pNF-H level was more elevated in cases of complete SCI. The level of CSF pNF-H was 10 to 100 times higher in complete SCI than in incomplete SCI, where the level was close to normal. The patients with a favorable neurological evolution after treatment had a specific pattern of daily values of NFP-H: a sudden increase up to a maximum value then a progressive decrease until normal. The maximum values were different in each case, from 10 times up to 200 times higher than the normal. Conclusions The phosphorylated form of the high molecular weight neurofilament subunit NF-H (pNF-H) in CSF is a specific biomarker for SCI and it can distinguish the severity of SCI. pNF-H is a predictive biomarker because its value pattern can show the reducing or stopping of the secondary lesion and the favorable result.