Progressive multifocal leukoencephalopathy (PML) is a severe disease of the central nervous system with very high mortality. It is caused by the JC virus with high seroprevalence, at up to 80%. Development of PML is typically opportunistic, particularly in acquired immunodeficiency syndrome, and usually affects patients with profound immunodeficiency. Furthermore, as a result of highly efficient immunosuppressive and immunomodulatory treatments in recent years, the number of PML cases has increased in the general population. In this article, the authors mention virological and epidemiological relationships and characteristic manifestations of PML. Possible relationships of humoral and cellular immunity are discussed and limited treatment options including prophylaxis are mentioned.
Keywords: CD4/CD8 ratio; HIV; cellular immunity; multiple sclerosis; progressive multifocal leukoencephalopathy.