HIV-negative "AIDS" in Kentucky: a case of idiopathic CD4+ lymphopenia and cryptococcal meningitis.

Here we describe a case of unexplained CD4+ T-lymphocyte depletion and cryptococcal meningitis in a patient without evidence of human immunodeficiency virus (HIV) infection. This newly recognized syndrome has been named idiopathic CD4+ lymphopenia (ICL). When HIV infection is suspected in a patient with an opportunistic infection, a CD4+ lymphocyte count should be obtained, even if the patient's HIV test is negative. Patients with persistently low CD4 counts (< 300 cells/microL, or < 20%) who show no evidence of HIV infection, who have no defined immunodeficiency, and who are not receiving therapy associated with CD4 depletion have disease that meets the definition of ICL, and the case should be reported to the Centers for Disease Control.