[Progressive multifocal leukoencephalopathy and rheumatic disease].

Progressive multifocal leukoencephalopathy (PML) is a rare but often fatal demyelinating disease of the central nervous system induced by the JC virus. It mainly occurs in immunocompromised patients. Growing interest in rheumatology has arisen from reports of patients with rheumatic diseases suffering from PML. A direct relationship to rheumatologic disease itself, for example systemic lupus erythematosus, or to immunosuppressive therapy, is debated. Therefore, PML should be included in the differential diagnosis of non-specific neurologic symptoms and, if suspected, relevant diagnostic procedures (MRI, CSF analysis including virus-specific PCR, and possibly brain biopsy) need to be performed.