NEFL and myeloid sarcoma: Although NfL is a non-specific marker of neuronal injuryand therefore not limited to MS, elevated serum NfL (sNfL) levels have beenassociated with acute relapse activity and responses to highly activetreatments42.Recently, the relevance of NfL in predicting disability accumulation has beenfurther explored, demonstrating that elevated sNfL levels after a firstdemyelinating event are associated with an increased risk of future disabilityaccumulation43.