Hemolysis or haemolysis, also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid. Hemolysis may occur in vivo or in vitro.
Spherocytosis is the presence of spherocytes in the blood, i.e. erythrocytes that are sphere-shaped rather than bi-concave disk shaped as normal. Spherocytes are found in all hemolytic anemias to some degree. Hereditary spherocytosis and autoimmune hemolytic anemia are characterized by having only spherocytes.
Glucose-6-phosphate dehydrogenase deficiency (G6PDD), which is the most common enzyme deficiency worldwide, is an inborn error of metabolism that predisposes to red blood cell breakdown. Most of the time, those who are affected have no symptoms. Following a specific trigger, symptoms such as yellowish skin, dark urine, shortness of breath, and feeling tired may develop. Complications can include anemia and newborn jaundice. Some people never have symptoms.
Hereditary spherocytosis (HS) is a congenital hemolytic disorder, wherein a genetic mutation coding for a structural membrane protein phenotype leads to a spherical shaping of erythrocytic cellular morphology. As erythrocytes are sphere-shaped (spherocytosis), rather than the normal biconcave disk-shaped, their morphology interferes with these cells' abilities to be flexible during circulation throughout the entirety of the body - arteries, arterioles, capillaries, venules, veins, and organs. This difference in shape also makes the red blood cells more prone to rupture under osmotic and/or mechanical stress. Cells with these dysfunctional proteins are degraded in the spleen, which leads to a shortage of erythrocytes resulting in hemolytic anemia.
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease of the blood characterized by destruction of red blood cells by the complement system, a part of the body's innate immune system. This destructive process occurs due to deficiency of the red blood cell surface protein DAF, which normally inhibits such immune reactions. Since the complement cascade attacks the red blood cells within the blood vessels of the circulatory system, the red blood cell destruction (hemolysis) is considered an intravascular hemolytic anemia. Other key features of the disease, such as the high incidence of venous blood clot formation, are incompletely understood.
Pyruvate kinase deficiency is an inherited metabolic disorder of the enzyme pyruvate kinase which affects the survival of red blood cells. Both autosomal dominant and recessive inheritance have been observed with the disorder; classically, and more commonly, the inheritance is autosomal recessive. Pyruvate kinase deficiency is the second most common cause of enzyme-deficient hemolytic anemia, following G6PD deficiency.
Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane in eukaryotic cells. Spectrin forms pentagonal or hexagonal arrangements, forming a scaffold and playing an important role in maintenance of plasma membrane integrity and cytoskeletal structure. The hexagonal arrangements are formed by tetramers of spectrin subunits associating with short actin filaments at either end of the tetramer. These short actin filaments act as junctional complexes allowing the formation of the hexagonal mesh. The protein is named spectrin since it was first isolated as a major protein component of human red blood cells which had been treated with mild detergents; the detergents lysed the cells and the hemoglobin and other cytoplasmic components were washed out. In the light microscope the basic shape of the red blood cell could still be seen as the spectrin-containing submembranous cytoskeleton preserved the shape of the cell in outline. This became known as a red blood cell "ghost" (spectre), and so the major protein of the ghost was named spectrin.
Hereditary elliptocytosis, also known as ovalocytosis, is an inherited blood disorder in which an abnormally large number of the person's red blood cells are elliptical rather than the typical biconcave disc shape. Such morphologically distinctive erythrocytes are sometimes referred to as elliptocytes or ovalocytes. It is one of many red-cell membrane defects. In its severe forms, this disorder predisposes to haemolytic anaemia. Although pathological in humans, elliptocytosis is normal in camelids.
Southeast Asian ovalocytosis is a blood disorder that is similar to, but distinct from hereditary elliptocytosis. It is common in some communities in Malaysia and Papua New Guinea, as it confers some resistance to cerebral Falciparum Malaria.
Hereditary stomatocytosis describes a number of inherited, mostly autosomal dominant human conditions which affect the red blood cell and create the appearance of a slit-like area of central pallor (stomatocyte) among erythrocytes on peripheral blood smear. The erythrocytes' cell membranes may abnormally 'leak' sodium and/or potassium ions, causing abnormalities in cell volume. Hereditary stomatocytosis should be distinguished from acquired causes of stomatocytosis, including dilantin toxicity and alcoholism, as well as artifact from the process of preparing peripheral blood smears.
The Kell antigen system is a human blood group system, that is, a group of antigens on the human red blood cell surface which are important determinants of blood type and are targets for autoimmune or alloimmune diseases which destroy red blood cells. The Kell antigens are K, k, Kpa, Kpb, Jsa and Jsb. The Kell antigens are peptides found within the Kell protein, a 93-kilodalton transmembrane zinc-dependent endopeptidase which is responsible for cleaving endothelin-3.
Protein 4.1,, is a protein associated with the cytoskeleton that in humans is encoded by the EPB41 gene. Protein 4.1 is a major structural element of the erythrocyte membrane skeleton. It plays a key role in regulating membrane physical properties of mechanical stability and deformability by stabilizing spectrin-actin interaction. Protein 4.1 interacts with spectrin and short actin filaments to form the erythrocyte membrane skeleton. Mutations of spectrin and protein 4.1 are associated with elliptocytosis or spherocytosis and anemia of varying severity.
Erythrocyte membrane protein band 4.2 is a protein that in humans is encoded by the EPB42 gene. It is part of the red blood cell cytoskeleton.
Aldolase A deficiency is an autosomal recessive metabolic disorder resulting in a deficiency of the enzyme aldolase A; the enzyme is found predominantly in red blood cells and muscle tissue. The deficiency may lead to hemolytic anaemia as well as myopathy associated with exercise intolerance and rhabdomyolysis in some cases.
Spectrin alpha chain, erythrocyte is a protein that in humans is encoded by the SPTA1 gene.
Spectrin beta chain, erythrocyte is a protein that in humans is encoded by the SPTB gene.
Haemochromatosis type 3 is a type of iron overload disorder associated with deficiencies in transferrin receptor 2. It exhibits an autosomal recessive inheritance pattern. The first confirmed case was diagnosed in 1865 by French doctor Trousseau. Later in 1889, the German doctor von Recklinghausen indicated that the liver contains iron, and due to bleeding being considered to be the cause, he called the pigment "Haemochromatosis." In 1935, English doctor Sheldon's groundbreaking book titled, Haemochromatosis, reviewed 311 patient case reports and presented the idea that haemochromatosis was a congenital metabolic disorder. Hereditary haemochromatosis is a congenital disorder which affects the regulation of iron metabolism thus causing increased gut absorption of iron and a gradual build-up of pathologic iron deposits in the liver and other internal organs, joint capsules and the skin. The iron overload could potentially cause serious disease from the age of 40–50 years. In the final stages of the disease, the major symptoms include liver cirrhosis, diabetes and bronze-colored skin. There are four types of hereditary hemochromatosis which are classified depending on the age of onset and other factors such as genetic cause and mode of inheritance.
Human genetic resistance to malaria refers to inherited changes in the DNA of humans which increase resistance to malaria and result in increased survival of individuals with those genetic changes. The existence of these genotypes is likely due to evolutionary pressure exerted by parasites of the genus Plasmodium which cause malaria. Since malaria infects red blood cells, these genetic changes are most common alterations to molecules essential for red blood cell function, such as hemoglobin or other cellular proteins or enzymes of red blood cells. These alterations generally protect red blood cells from invasion by Plasmodium parasites or replication of parasites within the red blood cell.
Erythrocyte fragility refers to the propensity of erythrocytes to hemolyse (rupture) under stress. It can be thought of as the degree or proportion of hemolysis that occurs when a sample of red blood cells are subjected to stress. Depending on the application as well as the kind of fragility involved, the amount of stress applied and/or the significance of the resultant hemolysis may vary.
Congenital dyserythropoietic anemia type II, or hereditary erythroblastic multinuclearity with positive acidified serum lysis test (HEMPAS) is a rare genetic anemia in humans characterized by hereditary erythroblastic multinuclearity with positive acidified serum lysis test.
