Progressive multifocal leukoencephalopathy in a patient treated with etanercept

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.