HIV coinfection rates were greater than 70% for all types of meningitis; the proportion of patients with CD4 cell counts below 100 cells/mm3 was 100% (9/9) for cryptococcal meningitis, 50% (5/10) for viral meningitis, 33% (5/15) for bacterial meningitis, and 0% (0/22) for TB meningitis. The gene discussed is CD4; the disease is viral meningitis.