Progressive multifocal leukoencephalopathy and idiopathic CD4+lymphocytopenia: a case report and review of reported cases.

Progressive multifocal leukoencephalopathy (PML) is a well recognized demyelinating neurological disorder caused by JC virus. Idiopathic CD4(+) lymphocytopenia (ICL) is a syndrome first described by the Centers for Disease Control and Prevention as a CD4(+) count <300 cells/mm(3) or a CD4(+) count that is <20% of the total T cell count on 2 occasions, with no evidence of human immunodeficiency virus (HIV) infection on testing, and absence of any defined immunodeficiency or therapy that depresses the levels of CD4(+) T cells. To the best of our knowledge, this is the third reported case of PML and ICL, and also the first reported case of the use of cidofovir to treat PML in a patient not infected with human immunodeficiency virus.