Abstract: Human immunodeficiency virus (HIV) infection causes progressive loss of CD4+T cells leading to AIDS.The mechanism of T cells deletion is not clearly understood.Apoptosis may be an important factor for the depletion.After HIV infection,continuous production of viral proteins leads to an unbalanced chronic immune activation,which is responsible for the disappearance of T helper cells primed for type-1 cytokine synthesis,thus contributing to the lack of survival factors which could prevent spontaneous lymphocyte apoptosis.The viral proteins or other factors also leads to the triggering of apoptotic programs,turning CD4+,CD8+T cells and APC,into effectors of apoptosis through Fas/FasL or other pathways.Many studies have showed that apoptosis may be responsible not only for the progressive loss of CD4+T cells but may be operative in CD8+T cells,B cells,NK cells,granuloblast,nerve cells and monocytes.Conclusively,Apoptosis,being a body self-defence mechanism,can not inhibit the replication and release of HIV in the reservoir of monocytes/macrophage,on the contrary,cause the death of many uninfected cells,which may lead to the lack of control of HIV replication and to the development of severe immune deficiency responsible for the occurrence of opportunistic infections associated with AIDS.