- HIV-1 initially infects T cells and macrophages directly or is carried to these cells by dendritic cells.
- Viral replication in the regional lymph nodes leads to viremia and widespread seeding of lymphoid tissue.
- The viremia is controlled by the host immune response, and the patient then enters a phase of clinical latency. During this phase, viral replication in both T cells and macrophages continues unabated, but there is some immune containment of virus.
- There continues a gradual erosion of CD4+ cells by productive infection or other mechanisms.
- When the CD4+ cells that are destroyed cannot be replenished, CD4+ cell numbers decline and the patient develops clinical symptoms of full-blown AIDS.
- Macrophages are also parasitized by the virus early; they are not lysed by HIV-1, and they can transport the virus to various tissues, particularly the brain.
Pathogenesis of AIDS and Replication of HIV