Evidence of the occurrence of anti-Tat Abs in the course of HIV infection was first reported in the late ’80s [110], and it soon became apparent that, unlike Abs against HIV structural proteins, Abs against Tat were only present in a minority of infected individuals [110,111], and that there was an inverse relationship between progression to disease (associated with p24 antigenemia, plasma viral load (VL) and CD4+ T-cell loss) and anti-Tat seropositivity [112,113,114,115]. This evidence concerns the gene TAT and HIV infectious disease.