Apoptosis of nucleated cells is well known

but how about the unnucleated cells is still not elucidated. In the present paper

the morphological and biochemical features of the aged erythrocytes were observed and compared with the characteristic events of apoptosis. Membrane of aged erythrocytes tends to shrink

protrude

from vesicle and lose lipid asymmetry. Aged erythrocytes were removed by phagocytosis. Both of the events are very similar to the apoptotic nucleated cells. The authors suggested that aging of erythro- cytes is also a process of apoptosis.