AUTHOR=Piñar-Morales Raquel , Calle-Calle Raquel , Carrasco-Garcia Maria , Davila-Arias Cristina , Villar-Guimerans Luisa Maria , Barrero Hernandez Francisco J. 

TITLE=Case Report: Neurofilament light chain in the follow up of progressive multifocal leukoencephalopathy in a patient with multiple sclerosis treated with ocrelizumab

JOURNAL=Frontiers in Pharmacology

VOLUME=Volume 16 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2025.1571699

DOI=10.3389/fphar.2025.1571699

ISSN=1663-9812

ABSTRACT=Progressive multifocal leukoencephalopathy (PML) results from the reactivation of John Cunningham virus JC virus and is a rare complication of anti-CD20 drug therapy. Neurofilament light chains increasingly serve as a marker of neuroaxonal damage in the follow-up of patients with multiple sclerosis (MS), but its role in the monitoring and detection of processes such as PML is yet to be defined. We report the case of a patient with MS who was treated with ocrelizumab and developed PML. Results: Serum neurofilament light chain (sNFL) levels were elevated at the diagnosis and progressively increased over his follow-up. Our results suggest that the monitoring of sNFL levels may be useful for the early diagnosis of PML in patients with MS.