Screening for neurodegeneration in Langerhans cell histiocytosis with neurofilament light in plasma

Patients with Langerhans cell histiocytosis (LCH) may develop progressive neurodegeneration in the central nervous system (ND‐CNS‐LCH). Neurofilament light protein (NFL) in cerebrospinal fluid (CSF) is a promising biomarker to detect and monitor ND‐CNS‐LCH. We compared paired samples of NFL in plasma (p‐NFL) and CSF in 10 patients (19 samples). Nine samples had abnormal CSF‐NFL (defined as ≥380 ng/l) with corresponding p‐NFL ≥ 2 ng/l. Ten samples had CSF‐NFL < 380 ng/l; eight (80%) with p‐NFL < 2 ng/l (p < 0.001; Fisher's exact test). Thus, our results suggest that p‐NFL may be used to screen for ND‐CNS‐LCH. Further studies are encouraged, including the role of p‐NFL for monitoring of ND‐CNS‐LCH.