CD4 and Kaposi's sarcoma: Since the advent of highly active antiretroviral therapy (HAART) in 1996, a reduction in the incidence of KS has been observed, which is more evident in high-income countries with access to treatment; for example, in the United States of America during the pre-HAART era (1991–1995), KS in patients with HIV was 500 to 2000 times more common than in the general population, particularly in those with high HIV viral loads and low CD4+ T-cell counts; after the advent of HAART, a consistent decrease of up to 6% of KS cases per year was observed [7,8].