JC Virus Replication at the First Symptoms of Multiple Sclerosis: A Case Report.

Multiple sclerosis (MS) is an autoimmune, demyelinating disorder of unknown etiology, in which viruses have been suggested as etiological/triggering agents. The attention to the association between viruses and MS has been rekindled by the development of progressive multifocal leukoencephalopathy in natalizumab-treated MS patients. Here we report the case of a woman with JC virus (JCV) replication in the cerebrospinal fluid, blood and urine collected at the first symptoms of MS and during several follow-up visits. This observation shows that JCV can be associated with MS without a relation with natalizumab treatment, although the triggering role of JCV in some cases of MS will require further studies.