Transformations of erythrocytes shape and its regulation

Erythrocytes can occur in many different shapes. Most of them are pathological and can be involved in diseases such a hemolytic anemia's and sickle cell anemia. Only three kinds of red blood cells are no pathological. Echinocytes, stomatocytes and discocytes can occure in blood stream of healthy organism. The echinocyte-dyscocyte-stomatocyte transformation protects red blood cells from lysis caused by echinocytogenic agents (hypertonic saline, basic pH, vanadate, anionic amphiphiles, ATP depletion etc.) or stomatocytogenic agents (hypotonic saline, acidic pH, cationic amphiphiles etc.). Mechanisms of these transformations can be classified in three group: redistribution of bilayer's lipid, modification Donnan's equilibrium and interaction of band 3 protein with different type of external factors.