Idiopathic CD4 lymphopenia associated with neuroinvasive West Nile disease: case report and review of the literature.

Idiopathic CD4 lymphocytopenia is a very rare condition resulting in an immunodeficiency disorder that may or may not result in opportunistic infections. Since its description in the early 1990s, the reason for this immune deficiency has remained unclear. Its association with viral illnesses, such as West Nile virus infection, has yet to be described. We report a 26-year-old patient who presented with fever, ascending paralysis, and progressive weakness of the upper extremities. To our knowledge, this is the first case of neuroinvasive West Nile virus occurring in the context of a diagnosis of idiopathic CD4 lymphocytopenia.