Progressive multifocal leukoencephalopathy in renal transplant recipients.

Progressive multifocal leukoencephalopathy, a slowly progressive papovavirus infection of the CNS, has been reported in more than 110 patients to date, over half of whom have had either leukemia or lymphoma. Our patient is the fourth case of PML occurring after long-term immunosuppression for renal transplantation. We believe that PML is emerging as a potentially serious problem in renal transplant recipients.