A blood type is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system. Some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens can stem from one allele and collectively form a blood group system.
Rh disease is a type of hemolytic disease of the fetus and newborn (HDFN). HDFN due to anti-D antibodies is the proper and currently used name for this disease as the Rh blood group system actually has more than 50 antigens and not only the D-antigen. The term "Rh Disease" is commonly used to refer to HDFN due to anti-D antibodies, and prior to the discovery of anti-Rho(D) immune globulin, it was the most common type of HDFN. The disease ranges from mild to severe, and occurs in the second or subsequent pregnancies of Rh-D negative women when the biologic father is Rh-D positive.
Glycophorin C plays a functionally important role in maintaining erythrocyte shape and regulating membrane material properties, possibly through its interaction with protein 4.1. Moreover, it has previously been shown that membranes deficient in protein 4.1 exhibit decreased content of glycophorin C. It is also an integral membrane protein of the erythrocyte and acts as the receptor for the Plasmodium falciparum protein PfEBP-2.
The ABO blood group system is used to denote the presence of one, both, or neither of the A and B antigens on erythrocytes. For human blood transfusions, it is the most important of the 44 different blood type classification systems currently recognized by the International Society of Blood Transfusions (ISBT) as of December 2022. A mismatch in this serotype can cause a potentially fatal adverse reaction after a transfusion, or an unwanted immune response to an organ transplant. Such mismatches are rare in modern medicine. The associated anti-A and anti-B antibodies are usually IgM antibodies, produced in the first years of life by sensitization to environmental substances such as food, bacteria, and viruses.
Paroxysmal cold hemoglobinuria (PCH) or Donath–Landsteiner hemolytic anemia (DLHA) is an autoimmune hemolytic anemia featured by complement-mediated intravascular hemolysis after cold exposure. It can present as an acute non-recurrent postinfectious event in children, or chronic relapsing episodes in adults with hematological malignancies or tertiary syphilis. Described by Julius Donath (1870–1950) and Karl Landsteiner (1868–1943) in 1904, PCH is one of the first clinical entities recognized as an autoimmune disorder.
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.
McLeod syndrome is an X-linked recessive genetic disorder that may affect the blood, brain, peripheral nerves, muscle, and heart. It is caused by a variety of recessively inherited mutations in the XK gene on the X chromosome. The gene is responsible for producing the Kx protein, a secondary supportive protein for the Kell antigen on the red blood cell surface.
The Lutheran antigen systems is a classification of human blood based on the presence of substances called Lutheran antigens on the surfaces of red blood cells. There are 19 known Lutheran antigens. The name Lutheran stems from a blood donor's misspelled last name, reportedly named Lutteran or Lutheran. All of these antigens arise from variations in a gene called BCAM. The system is based on the expression of two codominant alleles, designated Lua and Lub. The antigens Aua and Aub, known as the Auberger antigens, were once thought to make up a separate blood group but were later shown to be Lutheran antigens arising from variations in the BCAM gene.
Glycophorin A (MNS blood group), also known as GYPA, is a protein which in humans is encoded by the GYPA gene. GYPA has also recently been designated CD235a (cluster of differentiation 235a).
Glycophorin B (MNS blood group) (gene designation GYPB) also known as sialoglycoprotein delta and SS-active sialoglycoprotein is a protein which in humans is encoded by the GYPB gene. GYPB has also recently been designated CD235b (cluster of differentiation 235b).
Ecto-ADP-ribosyltransferase 4 is an enzyme that in humans is encoded by the ART4 gene. ART4 has also been designated as CD297.
Erythroid membrane-associated protein is a protein that in humans is responsible for the Scianna blood group system, and is encoded by the ERMAP gene.
In addition to the defined human blood group systems, there are erythrocyte antigens which do not meet the definition of a blood group system. Most of these are either nearly universal in human blood or extremely rare and are rarely significant in a clinical setting. Reagents to test for these antigens are difficult to find and many cannot be purchased commercially.
A kodecyte (ko•de•cyte) is a living cell that has been modified (koded) by the incorporation of one or more function-spacer-lipid constructs to gain a new or novel biological, chemical or technological function. The cell is modified by the lipid tail of the FSL construct incorporating into the bilipid membrane of the cell.
Rh blood group, D antigen also known as Rh polypeptide 1 (RhPI) or cluster of differentiation 240D (CD240D) is a protein that in humans is encoded by the RHD gene.
Johannes Jacobus (Joghem) van Loghem (1914-2005), was a professor of internal medicine at the Wilhelmina Gasthuis in Amsterdam renowned for his work in blood group serology and immunohaematology.
The Vel blood group is a human blood group that has been implicated in hemolytic transfusion reactions. The blood group consists of a single antigen, the high-frequency Vel antigen, which is expressed on the surface of red blood cells. Individuals are typed as Vel-positive or Vel-negative depending on the presence of this antigen. The expression of the antigen in Vel-positive individuals is highly variable and can range from strong to weak. Individuals with the rare Vel-negative blood type develop anti-Vel antibodies when exposed to Vel-positive blood, which can cause transfusion reactions on subsequent exposures.
The monocyte monolayer assay (MMA) is used to determine the clinical significance of alloantibodies produced by blood transfusion recipients. The assay is used to assess the potential for intravascular hemolysis when incompatible cellular blood products are transfused to the anemic patient. When donor cells possess substances that are not produced by the recipient, the recipient's immune system produces antibodies against the substance; these are called alloantibodies. Specific white blood cells, called monocytes, are tasked with ingesting foreign material and become activated during certain inflammatory events. These activated monocytes come in contact with antibody-sensitized red blood cells (RBC) and may or may not exhibit phagocytosis (ingestion) and destroy the donor red blood cells. If monocytes destroy the RBC, the antibody attached to those RBC is considered clinically significant.
Marion Elizabeth Reid is a British scientist specialising in immunohematology and author based in Bristol. She has worked in both the United Kingdom and the United States.
Anneke Brand (1946-2021) was a Dutch physician-scientist whose work on platelet and red blood cell transfusion and cord blood transplantation earned her transfusion medicine’s three highest honors: the AABB Karl Landsteiner Memorial Award; International Society of Blood Transfusion Presidential Award; and the British Blood Transfusion Society James Blundell Award.
