A study on HIV-infected individuals who manifested PML, and where more than half of them were treated with HAART, revealed that almost all patients had a nadir CD4+ cell count < 200 cells/μL, very few patients had a fever and leukocytosis, but about half of them had an elevated sedimentation rate or C-reactive protein level; CD4+ cell count > 50 cells/μL at PML diagnosis was significantly linked to reduced mortality [88]. The gene discussed is CD4; the disease is Fever.