Cidofovir treatment of progressive multifocal leukoencephalopathy in a patient receiving highly active antiretroviral therapy

Progressive multifocal leukoencephalopathy (PML), a frequently fatal demyel inating disease caused by JC virus, occurs as an opportunistic infection in patients with acquired immunodeficiency syndrome. Curative therapy has bee n elusive, but recent reports suggest its improvement after institution of highly active antiretroviral therapy (HAART). We describe a case of PML tha t developed 6 months after the patient, a 55-year-old man, began to receive HAART. The PML progressed despite good virologic and immunologic response to HAART. Substantial symptomatic and radiographic improvement occurred aft er the addition of cidofovir to the treatment regimen. We reviewed the scie ntific literature on this rare occurrence of PML after institution of HAART and describe the patient characteristics, potential pathogenesis, and ther apeutic options, including the successful use of cidofovir as an adjunctive agent.