A summary of theories on how immune cells are destroyed in the replication process of HIV follows:
- The process of viral budding tears a hole in the host cell membrane, causing cytoplasmic leakage.
- Chronic/hyperimmune activation results in rapid turnover with a decrease of immune cells due to shortened life span, and they are lost quickly when activated.
- Immune activation and inflammation result in high levels of proinflammatory agents, including cytokines that will deplete immune cells.
- Pyropoptosis is a process of extreme inflammatory response in which dying cells release cytokines that trigger pyroptosis in other T cells resulting in CD4 cell depletion.
- Regulatory T cells (Treg) are important in limiting immunopathology by suppressing activation, proliferation, and effector function of T lymphocytes in order to maintain homeostasis. In HIV infection where CD4 cells are depleted, there is some evidence that Treg cells continue to remain high further contributing to immune depletion.
