Cellular suicide, also known as programmed cell death. HIV may induce apoptosis in both infected and uninfected 
immune system cells. Uninfected cells may also undergo apoptosis. Normally when CD4+ 
T cells mature in the 
thymus gland, a small proportion of these cells are unable to distinguish self from nonself. Because these cells would otherwise attack the body's own tissues, they receive a biochemical signal from other cells that results in apoptosis. See also 
CD4 (
T4) or CD4+ Cells; 
Thymus.