Editors' note: Blood NfL: A biomarker for disease severity and progression in Parkinson disease

Abstract

In “Blood NfL: a biomarker for disease severity and progression in Parkinson disease,” Lin et al. reported that neurofilament light chain (NfL) levels are significantly higher in patients with multiple system atrophy (MSA) than patients with Parkinson disease (PD) or healthy controls and that, for patients with PD, NfL levels increase with disease severity. Van Rumund et al. agreed that NfL could distinguish PD from MSA but questioned the finding that NfL increases with disease severity in patients with PD because (1) they previously found that NfL levels in patients with PD to be similar to controls, (2) the determination of NfL cutoff values and the assessment for the relationship between PD disease progression and blood NfL were performed in the same population, and (3) the definitions used to define motor and cognitive decline may be overly sensitive. However, Van Rumun et al. and Lin and Chiu both suggested that the differences in their NfL level findings in patients with PD may be explained by a greater number of patients with advanced PD in the study of Lin et al. Although NfL may be a useful biomarker to distinguish MSA from PD, further research is needed on the role of NfL as a marker of PD disease progression. In “Blood NfL: a biomarker for disease severity and progression in Parkinson disease,” Lin et al. reported that neurofilament light chain (NfL) levels are significantly higher in patients with multiple system atrophy (MSA) than patients with Parkinson disease (PD) or healthy controls and that, for patients with PD, NfL levels increase with disease severity. Van Rumund et al. agreed that NfL could distinguish PD from MSA but questioned the finding that NfL increases with disease severity in patients with PD because (1) they previously found that NfL levels in patients with PD to be similar to controls, (2) the determination of NfL cutoff values and the assessment for the relationship between PD disease progression and blood NfL were performed in the same population, and (3) the definitions used to define motor and cognitive decline may be overly sensitive. However, Van Rumun et al. and Lin and Chiu both suggested that the differences in their NfL level findings in patients with PD may be explained by a greater number of patients with advanced PD in the study of Lin et al. Although NfL may be a useful biomarker to distinguish MSA from PD, further research is needed on the role of NfL as a marker of PD disease progression.