Case Reports/Case SeriesProgressive Multifocal Leukoencephalopathy in a Patient Treated With EtanerceptGraff-Radford, Jonathan MD*; Robinson, Maisha T. MD*; Warsame, Rahma M. MD†; Matteson, Eric L. MD†; Eggers, Scott D. Z. MD*; Keegan, B. Mark MD, FRCP(C)*Author Information Departments of *Neurology †Internal Medicine, Mayo Clinic, Rochester, MN Keegan is compensated as a section editor for Neurology, and as Chief Editor of eMedicine and served in a 1-time capacity as a consultant to Novartis in a mock FDA review for the medication fingolimod. More than 24 months ago, Dr Matteson was a consultant to Amgen and received <$10,000. The authors declare no conflict of interest. Reprints: B. Mark Keegan, MD, FRCP(C), Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905. E-mail: [email protected]. The Neurologist: March 2012 - Volume 18 - Issue 2 - p 85-87 doi: 10.1097/NRL.0b013e318247b868 Buy Metrics Abstract Introduction: Recently, increased attention has been paid to the association of progressive multifocal leukoencephalopathy (PML) with the use of immunomodulatory medications for autoimmune diseases. Case Report: A 23-year-old Native American woman with a history of systemic lupus erythematosus and erosive polyarthritis treated with prednisone and etanercept presented with focal weakness, hemiataxia, diplopia, and dysarthria. Brain magnetic resonance imaging demonstrated progressive, T2 signal hyperintensities within the brainstem and cerebellar white matter without mass effect or gadolinium enhancement. Cerebrospinal fluid showed elevated protein and JC virus polymerase chain reaction positive with 28,600 copies/ml diagnostic of PML. Conclusions: The development of PML in this patient treated with etanercept and prednisone highlights the increased risk for opportunistic infection with JC virus in patients with autoimmune diseases on immunosuppressive therapies. © 2012 Lippincott Williams & Wilkins, Inc.