CD4 and infection: From an early stage of infection, HIV is known to subvert dendritic cell and macrophage activities to enhance its own replication at mucosal locations.158 In addition, intestinal CD4 + T-cells (which express high levels of the CCR5 co-receptor which facilitates entry of HIV virions into these cells) are significantly depleted.159 At both the mucosal level and within the gut, particularly, HIV contributes to progressive degradation of the immune system, and thus enables evasion by several microorganisms from routine immune system surveillance.