1) Bloomgren G, Richman S, Hotermans C, et al:Risk of natalizumab-associated progressive multifocal leukoencephalopathy. N Engl J Med 2012;17(366):1870-80 2) Ho PR, Koendgen H, Campbell N, et al:Risk of natalizumab-associated progressive multifocal leukoencephalopathy in patients with multiple sclerosis:a retrospective analysis of data from four clinical studies. Lancet Neurol 2017;16:925-33 3) Wenning W, Haghikia A, Laubenberger J, et al:Treatment of progressive multifocal leukoencephalopathy associated with natalizumab. N Engl J Med 2009;361:1075-80 4) Lindå H, von Heijne A, Major EO, et al:Progressive multifocal leukoencephalopathy after natalizumab monotherapy. N Engl J Med 2009;361:1081-7 5) Clifford DB, De Luca A, Simpson DM, et al:Natalizumab-associated progressive multifocal leukoencephalopathy in patients with multiple sclerosis:lessons from 28 cases. Lancet Neurol 2010;9:438-46 6) Vermersch P, Kappos L, Gold R, et al:Clinical outcomes of natalizumab-associated progressive multifocal leukoencephalopathy. Neurology 2011;76:1697-704 7) Dahlhaus S, Hoepner R, Chan A, et al:Disease course and outcome of 15 monocentrically treated natalizumab-associated progressive multifocal leukoencephalopathy patients. J Neurol Neurosurg Psychiatry 2013;84:1068-74 8) http://www.ms-supportnavi.com/med/tys/products/08.html 9) Landi D, De Rossi N, Zagaglia S, et al:No evidence of beneficial effects of plasmapheresis in natalizumab-associated PML. Neurology 2017;88:1144-52 10) https://www.uptodate.com/contents/progressive-multifocal-leukoencephalopathy-treatment-andprognosis?/souece=see_link§ionName=Natalizumab-associated%20PML&anchor=H56321583#56321583 11) Clifford DB:Neurological immune reconstitution inflammatory response:riding the tide of immune recovery. Curr Opin Neurol 2015;28:295-301 12) N'gbo N'gbo Ikazabo R, Mostosi C, Quivron B, et al:Immune-reconstitution inflammatory syndrome in multiple sclerosis patients treated with natalizumab:A series of 4 cases. Clin Ther 2013;38(3):670-5 13) Vennegoor A, Rispens T, Van Oosten BW, et al:Application of serum natalizumab levels during plasma exchange in MS patients with progressive multifocal leukoencephalopathy. Mult Scler 2015;21(4):481-4 14) Takao M:Targeted therapy and progressive multifocal leukoencephalopathy(PML):PML in the era of monoclonal antibody therapies. Brain Nerve 2013;65(11):1363-74 15) Wattjes MP, Verhoeff L, Zentjens W, et al:Punctate lesion pattern suggestive of perivascular inflammation in acute natalizumab-associated progressive multifocal leukoencephalopathy:productive JC virus infection or preclinical PML-IRIS manifestation? J Neurol Neurosurg Psychiatry 2013;84(10):1176-7 16) Subramanyam M, Plavina T, Khatri BO, et al:The effect of plasma exchange on serum anti-JC virus antibodies. Mult Scler 2013;19(7):912-9 17) Gwathmey K, Balogun RA, Burns T:Neurologic indications for therapeutic plasma exchange:2011 update. J Clin Apher 2012;27(3):138-45