Comparison of CSF and blood neurofilament light (NfL) and heavy chain (NfH) as prognostic biomarker for ALS

We conducted a prospective study involving patients diagnosed with ALS according to the Gold Coast criteria at Razi University Hospital in Tunisia. Participants were classified based on their rates of disease progression. We measured NfL and NfH levels in both cerebrospinal fluid (CSF) and blood using ELISA technology. Subsequently, we examined the correlation between Nfs levels in CSF and blood, as well as their relationship with various clinical features of ALS

We included 40patients with a mean age at onset of 54.24 years and a sex ratio of 1.78. Of these patients, 34 had spinal ALS and 6 with bulbar onset.

Measurements of Nfs showed a strong correlation between cerebrospinal fluid (CSF) and blood (rho=0.836, p<0.0001 for NfL and rho=0.641, p<0.01 for NfH). We found a significant association between NfL concentrations and bulbar onset (rho=0.493, p<0.0001; rho=0.525, p<0.0001). Conversely, the correlation between NfL values in both biofluids and ALSFRS-R scores was weaker (rho=0.206, p=0.023; rho=0.217, p=0.006). Furthermore, patients with rapid progression, regardless of ALS subtype, exhibited higher NfL levels than those with slower progression (p=0.026).

Regarding Neurofilament Heavy Chain (NfH), we observed elevated levels in ALS patients, along with a strong correlation between NfL and NfH values. Additionally, NfH levels were negatively correlated with the ALS disease course (rho=-0.72, p=0.036).

Nfs are effective ALS biomarkers, with high levels linked to disease onset, progression, and ALSFRS-R scores. Blood is preferred for Nfs measurement due to its non-invasive nature, showing similar results to CSF.