HIV: human immunodeficiency syndrome; AIDS: acquired immunodeficiency syndrome; CD4: cluster of differentiation 4; HAART: highly active antiretroviral therapy; MRSA: methicillin-resistant Staphylococcus aureus; ARDS: acute respiratory distress syndrome; NICU: neonatal intensive care unit; CLD: chronic liver disease; CPAP: continuous positive airway pressure; BIPAP: bilevel positive airway pressure. The gene discussed is CD4; the disease is AIDS.