Two cases of progressive multifocal leukoencephalopathy after renal transplantation.

Progressive multifocal leukoencephalopathy (PML) occurred in two patients after kidney transplantation. Less than 2 years after such a transplantation associated with immunosuppressive chemotherapy a 54-year-old male developed polyneuropathy then clinical diffuse alteration of the central nervous system. He died three months later with the suspicion of hypertensive encephalopathy due to progressive renal failure. A 45-year-old female had a kidney transplantation first rapidly complicated by Listeria monocytogenes meningoencephalitis. She was cured from this disease and had a satisfactory social rehabilitation during two years. Afterwards, she suffered various neurological troubles, including epilepsy, that were attributed to combined renal failure and developing hydrocephalus. One year after the onset of these neurological symptoms, the grafted kidney was removed and chemotherapy was discontinued. She died three months later. Both patients had typical PML with eosinophilic intranuclear inclusions in presumptive oligodendroglial cells. By electron microscopy, performed on formalin fixed brain tissue, round particles (40-50 nm) could be recognized in some glial cell nuclei. These two cases are confronted with the four published observations of PML following organ transplantation.