Neurofilament Light Chain in Cerebrospinal Fluid and Blood as a Biomarker for Neurodegenerative Diseases: A Systematic Review and Meta-Analysis

Background Neurofilament light chain (NFL) as a potential biomarker of neurodegenerative diseases has been studied in a number of studies. Thus, a comprehensive meta-analysis is warranted to assess NFL performance in neurodegenerative diseases. Objective To assess the performance of NFL in blood and cerebrospinal fluid (CSF) as a biomarker for neurodegenerative diseases. Methods A total of 36 studies with comparison of NFL level between individuals with neurodegenerative diseases and controls were retrieved from PubMed, Web of Science and Science Direct, and the ratio of means method and delta method based on the random-effect model were used to analyze the differentiation of NFL between patients and controls. Results Differentiation of CSF NFL between patients with neurodegenerative diseases and controls showed significant results. Although a few studies on blood NFL available were included in the meta-analysis, the results still showed a distinct possibility that NFL could be a potential biomarker for neurodegenerative diseases. NFL levels were increased significantly in dementias, amyotrophic lateral sclerosis, Creutzfeldt-Jakob disease, and Huntington's disease. By contrast, NFL levels were not increased in Parkinson's disease (PD), although they were increased significantly in PD-related disorders (multiple system atrophy and progressive supranuclear palsy). Conclusions In our study, in addition to PD, NFL was suggested to be a global diagnostic biomarker for neurodegenerative diseases. Moreover, it could be used in differential diagnosis of PD and PD-related disorders. However, it was worth noting that NFL was not appropriate for diagnosis or differential diagnosis without clinical symptoms and other auxiliary examinations.