In HIV infection of human macrophages and microglia in vitro, 50 – 60% increases in surface CCR5 increased HIV entry by 588 – 985% (79), while increasing CCR5 expression approximately 300%, from 7 x 102 to 2 x 103 CCR5 molecules in a HeLa indicator cell line increased HIV infectivity titers more than three orders of magnitude (80). Here, CCR5 is linked to HIV infectious disease.