Aye know that Most Do Not In form How out Score is Based,
the Milk of butter is Toast??,
Mel is the Arrow^EAN of this Course,
is the Next on line a Avenue or a Bond??.
Did the bell ring Dial or Answer to the for Inch of the Weight on that Hinge or Knock,
at porch is a brick,
on say is the role Lee pull lee,
mew knee is knot SAM bow,
the Bill bored Is On jaw Knows capacity to Thor!!
Chase the sound to Watt Tunnel on the Stockton Bull a Vard,
round to the Lombard over touch out,
the Pink Hip Poe is a design of Locale or designate Shun,
shall the Dancing Bare be of Barrel or Pickle brine to 'V' last Tick??,
mi Ow mire is the Soaking bale of eh Batch to Squall on Pigeon,
kelp See is Moss?? or the *Kell see Cray^On to Draw or speak as seal Rock in as A view too.
Depth is Corner??,
of store is blank??,
just A fie'd by the Cover to shield the big goldfish as coy!!
*Kell antigen system
From Wikipedia, the free encyclopedia
| Kell protein | |
|---|---|
| Identifiers | |
| Symbol | KEL |
| Alt. symbols | ECE3, CD238 |
| Entrez | 3792 |
| HUGO | 6308 |
| OMIM | 110900 |
| RefSeq | NM_000420 |
| UniProt | P23276 |
| Other data | |
| Locus | Chr. 7 q33 |
The Kell antigen system (also known as Kell–Cellano system) 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. Kell can be noted as K, k, or Kp.[1][2] The Kell antigens are peptides found within the Kell protein, a 93-kilodalton transmembrane zinc-dependent endopeptidase which is responsible for cleaving endothelin-3.[3][4]
Contents
[hide]Protein[edit]
The KEL gene encodes a type II transmembrane glycoprotein that is the highly polymorphic Kell blood group antigen. The Kell glycoprotein links via a single disulfide bond to theXK membrane protein that carries the Kx antigen. The encoded protein contains sequence and structural similarity to members of the neprilysin (M13) family of zincendopeptidases.[5]
There are several alleles of the gene which creates Kell protein. Two such alleles, K1 (Kell) and K2 (Cellano), are the most common. The kell protein is tightly bound to a second protein, XK, by a disulfide bond. Absence of the XK protein (such as through genetic deletion), leads to marked reduction of the Kell antigens on the red blood cell surface. Absence of the Kell protein (K0), however, does not affect the XK protein.[6]
The Kell protein has also recently been designated CD238 (cluster of differentiation 238).
Disease association[edit]
Kell antigens are important in transfusion medicine, autoimmune hemolytic anemia and hemolytic disease of the newborn (anti-Kell). Anti-K is the next most common immune red cell antibody after those in the ABO and Rh system. Anti-K typically presents as IgG class alloantibody. Individuals lacking a specific Kell antigen may develop antibodies against Kell antigens when transfused with blood containing that antigen. This is particularly true for the "K" antigen which shows a relatively high antigenicity and moderately low frequency (~9%) in Caucasian populations. Anti-K can also occur following transplacental hemorrhage (TPH) associated with childbirth making Kell an important concern forhemolytic disease of the newborn. Following the formation of anti-K, subsequent blood transfusions may be marked by destruction of the new cells by these antibodies, a process known as hemolysis. Anti-K does not bind complement, therefore hemolysis is extravascular. Individuals without K antigens(K0) who have formed an antibody to a K antigen, must be transfused with blood from donors who are also K0 to prevent hemolysis.
Autoimmune hemolytic anemia (AIHA) occurs when the body produces an antibody against a blood group antigen on its own red blood cells. The antibodies lead to destruction of the red blood cells with resulting anemia. Similarly, a pregnant woman may develop antibodies against fetal red blood cells, resulting in destruction, anemia, and hydrops fetalis in a process known as hemolytic disease of the newborn (HDN). Both AIHA and HDN may be severe when caused by anti-Kell antibodies,[7] as they are the most immunogenic antigens after those of the ABO and Rhesus blood group systems.
McLeod phenotype[edit]
Main article: McLeod syndrome
McLeod phenotype (or McLeod syndrome) is an X-linked anomaly of the Kell blood group system in which Kell antigens are poorly detected by laboratory tests. The McLeod gene encodes the XK protein, a protein with structural characteristics of a membrane transport protein but an unknown function. The XK appears to be required for proper synthesis or presentation of the Kell antigens on the red blood cell surface.
History[edit]
The Kell group was named after the first patient described with antibodies to K1, a pregnant woman named Mrs. Kellacher in 1945.[8] Mrs. Cellano was likewise a pregnant woman with the first described antibodies to K2. The K0 phenotype was first described in 1957 and the McLeod phenotype was found in Hugh McLeod, a Harvard dental student, in 1961.[9][10] There is recent information speculating that King Henry VIII of England had Kell-positive blood type, explaining the deaths of seven of his ten children at, or soon after, birth, and suggesting that his mental deterioration around age 40 could be explained by McLeod Syndrome.[11]
Other associations[edit]
Evidence supports a genetic link between the Kell blood group (on chromosome 7 q33) and the ability to taste phenylthiocarbamide, or PTC, a bitter-tasting thioureacompound.[12][13] Bitter taste receptor proteins in the taste buds of the tongue that recognise PTC are encoded on nearby chromosome locus 7 q35-6.