Blood neurofilament light chain measurements in adults with CNS histiocytic neoplasms

Histiocytic neoplasms constitute a group of rare hematologic neoplasms characterized by the accumulation of neoplastic histiocytic/dendritic cells with associated inflammatory infiltrate [ 1 ]. Central nervous system (CNS) involvement of these neoplasms is associated with increased morbidity and mortality [ 2 , 3 ]. Contrast-enhanced brain and spine MRI is the current standard for evaluating for the presence of CNS disease and monitoring response to treatment [ 4 ]. Neurofilament light chain (NfL) is a recently identified biomarker of axonal degeneration that has been utilized in monitoring disease activity in a wide variety of neurologic diseases [ 5 ]. It has extensive potential clinical utility as it can be tested in blood. The aim of this study was to evaluate if elevated NfL in patients with histiocytic neoplasms is associated with CNS involvement and active CNS disease.