CD4 and AIDS: Recent findings from the strategic timing of antiretroviral treatment (START) study[6] conducted at 215 sites in 35 countries, revealed that starting ART immediately rather than later (CD4 counts <350 cells/μl or at AIDS-defining illness) resulted in a 53% reduction in risk of developing serious AIDS-related events (e.g., AIDS-related cancer) or non-AIDS related events (major cardiovascular, renal and liver disease, non-AIDS cancer) and death.