Association of serum neurofilament light chain levels with clinicopathology of chronic inflammatory demyelinating polyneuropathy, including NF155 reactive patients

Objectives To clarify whether serum neurofilament light chains (NfLs) serve as a biomarker of axonal damage in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), especially in patients with anti-neurofascin 155 (NF155) antibodies. Methods The Simoa system was used to examine serum NfL levels from 58 patients with CIDP, including 13 anti-NF155 antibody-positive patients, and from 14 age- and sex-matched healthy individuals. Serum NfL levels were evaluated before and after treatment in eight patients with anti-NF155 antibodies. Clinical features, electrophysiological findings, and cerebrospinal fluid (CSF) protein levels, were evaluated. The pathological features of sural nerves from 40 patients were also examined. Results Serum NfL levels were significantly higher in patients with CIDP than in healthy individuals (median 29.63 vs. 7.71 pg/mL, p < 0.001) and were correlated with both modified Rankin Scale scores (r = 0.584, p < 0.001) and CSF protein levels (r = 0.432, p = 0.001). The NfL levels of anti-NF155 antibody-positive patients were higher than those of antibody-negative patients (p = 0.005). Serum NfL levels were negatively correlated with compound muscle action potential amplitudes of the tibial nerves (r = - 0.404, p = 0.004) and positively correlated with the degree of active axonal degeneration in the pathological findings (r = 0.485, p = 0.001). In the antibody-positive group, NfL levels and antibody titers decreased after treatment in all examined patients. Conclusion Serum NfL correlated with pathological indices of axonal degeneration, and may serve as a biomarker that reflects active axonal damage of CIDP.