Measuring Neurofilament Levels Might Improve Diagnosis of Early Symptomatic ALS

Routinely measuring neurofilaments in the blood and spinal fluid of people with amyotrophic lateral sclerosis (ALS) can help identify patients with early symptoms, concludes a recent study.

Researchers led by Dr. Emily Feneberg of England’s University of Oxford presented the study, “Multicenter evaluation of neurofilaments in early symptom onset amyotrophic lateral sclerosis,” at the 3rd Congress of the European Academy of Neurology in Amsterdam.

The main components of neuronal cells are phosphorylated neurofilament heavy chain (pNfH) and the neurofilament light chain (NfL). But when neurons die, these components are released and be detected in both the blood and cerebrospinal fluid (CFS).

While this suggests that blood and CSF neurofilaments could be biomarkers for ALS, scientists are still unsure. That led Feneberg and her team to investigate the timing of neurofilament release in patients with sporadic ALS.

Researchers conducted their study at nine research centers across Europe, which each one providing at least five CFS and blood samples from patients in the early stages of ALS — symptom onset six months prior from sample collection. Each center also provided CFS or blood samples from patients with later-stage ALS, other neurologic diseases and motor neuron diseases for comparison.

The research team found that patients with early and later symptomatic-phase ALS had higher levels of NfL and pNfH than did all other patient groups. But while NfL levels were similar among ALS patients, they were higher in the early symptomatic than in the later phase.

“CSF and serum NfL and CSF pNfH levels are significantly elevated in ALS patients seen in the first months after symptom onset, even in patients who would be clinically characterized as only suspected ALS,” the researchers wrote.

No significant differences were observed in CSF NfL and pNfH levels among ALS patients when divided according to El Escorial diagnostic criteria. These findings suggest that routine measurement of neurofilaments in motor neuron disease centers can aid ALS diagnosis independently of the clinical diagnostic criteria status.

“[Evaluation of] neurofilaments in ALS strongly enhance the diagnostic accuracy for inclusion into clinical trials in an early disease phase,” they said.