Neurol Neuroimmunol Neuroinflamm 2021 01 13;8(1). Epub 2020 Oct 13.
From the Department of Neurology (A.A.T., Z.Y.G.L., E.E.M.S., B.A.J., Z.L.E.K., J.K.), Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, MS Center Amsterdam; Department of Clinical Chemistry (C.E.T.), Neurochemistry Laboratory and Biobank, Amsterdam Neuroscience, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam; Department of Ophthalmology (A.P.), Neuro-ophthalmology Expertise Center, Amsterdam Neuroscience, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Department of Diagnostic and Interventional Neuroradiology (M.P.W.), Hanover Medical School, Hanover, Germany; Department of Radiology and Nuclear Medicine (M.P.W., F.B.), Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, MS Center Amsterdam, the Netherlands; Department of Neuroinflammation (F.B.), Queen Square MS Centre, UCL Institute of Neurology, Faculty of Brain Sciences, University College London; and National Institute for Health Research (NIHR) University College London Hospitals (UCLH) Biomedical Research Centre (F.B.), London, United Kingdom.
Objective: To describe the disease course of carryover progressive multifocal leukoencephalopathy (PML) after switching from natalizumab to ocrelizumab in 2 patients with relapsing-remitting MS.
Methods: Two case reports with 1 year of follow-up and retrospective longitudinal measurements of serum neurofilament light (NfL) levels and B-cells.
Results: PML was diagnosed 78 days (case 1) and 97 days (case 2) after discontinuation of natalizumab. Both patients developed mild immune reconstitution inflammatory syndrome (IRIS) despite B-cell depletion caused by ocrelizumab. NfL levels increased in both patients during PML-IRIS. PML-IRIS lesions stabilized after treatment with mefloquine and mirtazapine, followed by methylprednisolone, and both patients continued therapy with ocrelizumab when B-cells started to repopulate.
Conclusions: The clinical course of carryover PML was mild in both patients, suggesting that B-cell depletion possibly did not aggravate PML-IRIS in these 2 patients.