Early in the HIV epidemic, it was observed that individuals homozygous for the CCR5-\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\Delta$$\end{document}Δ 32 mutation, which renders CCR5 nonfunctional, were resistant to HIV infection and lacked significant immunological defects [558, 559]. This evidence concerns the gene CCR5 and HIV infectious disease.