Background: Progressive multifocal leukoencephalopathy (PML) is a rare, rapidly progressive, demyelinating disease of the brain caused by polyoma JC virus. It occurs in immunocompromised patients, including those after solid organ and bone marrow transplantations. We present the clinically diagnosed case of PML in a renal allograft recipient. Case Report: A 34-year-old male kidney transplant patient receiving triple-drug (cyclosporine, azathioprine, prednisone) immunosuppressive treatment for 60 months complained of progressive visual loss, vertigo and weakness of the hand. He had congenital strabismus, severe hyperopia, a freshly diagnosed corticosteroid-induced cataract, and normal retinas and optic disks. Magnetic resonance imaging of the brain showed large, multifocal, asymmetric, nonenhancing white matter lesions in the periventricular and subcortical areas, which were strongly characteristic of PML. Both cytomegalovirus IgM antibodies in serum and DNA in cerebrospinal fluid were detected, and the patient was treated with gancyclovir. He was also switched to mycofenolate mofetil because of the possibility of cyclosporine-induced leukoencephalopathy. Despite the therapy, the patient showed relentless neurobehavioral deficits, and died in coma 5 months after the presentation. Conclusions: PML is an infrequent but fatal disease. Renal and other transplant recipients with neurobehavioral disturbances should be promptly investigated for PML and other demyelinating diseases of the brain. Special attention should be paid to those with a corticosteroid-induced cataract and progressive visual complaints.

Keywords: JC polyoma virus, progressive multifocal leukoencephalopathy, Kidney Transplantation