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.