CD4 and tuberculosis: Most recently, in the HPTN 052 multi-centre trial featuring study sites in Botswana, Brazil, India, Kenya, Malawi, South Africa, Thailand, the United States, and Zimbabwe, there were 3 cases of TB in those starting ART with CD4 counts between 350 and 550 cells/ mm3, and 17 cases in those randomised to defer ART until their CD4 count dropped below 250 cells/ mm3 (p-value 0.002) [57].