HIV infection induces a profound immune dysfunction, with abnormalities in cellular and humoral immune responses, including (i) CD4 lymphopenia, (ii) neutropenia, (iii) decreased NK cell-mediated cytotoxicity, (iv) decreased phagocytosis, chemotaxis, intracellular killing, and cytokine expression in monocytes, (v) decreased B cell number, and (vi) loss of specific antibody response [90,91]. Here, CD4 is linked to HIV infectious disease.