A blood test for antigens is performed before a blood transfusion to find out if there is a risk of donor red blood cell rejection. The Kell antigen system has 25 located directly on red blood cells. If none of them are found in the analysis of the recipient, then the donor must be sought among those who also do not have these antigens. The international protein differentiation system Kell antigen was also included in the list; it received code CD238.
Blood system antigens sometimes cause hemolytic disease in newborns. Now every pregnant woman should pass the test and know what her Kell antigen is: positive or negative. And also the test is required to pass the pregnant husband.
What is a Kell-cellano system?
The Kell system is a system of antigens that are located on the surface of red blood cells, like the more well-known Rh protein. Proteins of the Kell-cellano system serve as a target for immune cells. Therefore, when Kell-negative blood is mixed with Kell-positive, the negative group's immune cells attack the “foreign” proteins, that is, a bright immune reaction to foreign red blood cells begins.
The Kell antigen system is in fact the next third after the Rh factor system. But there are other antigens, for example, the Lutheran, Daffy system and others.
The Kell system consists of only 2 antigens. There are 3 groups of blood, they look as follows - Kk, KK and kk or K0, K1, K2. That is, Kell-positive, Kell-negative blood and the Macleod phenotype are isolated.
A separate group - the Macleod (MacLeod) phenotype - is an anomaly in which it is not always possible to detect Kell antigens in the laboratory. They are few in blood, but they are. It is believed that the anomaly is associated with the Macleod gene, which blocks the protein necessary for the synthesis of the mentioned protein.
Discovery story
In 1945, the patient was first discovered - Mrs. Kellacher. This woman found antibodies in the blood against a protein then unknown. Later, a pregnant woman was discovered in the blood of which K2 antibodies were present, her surname Kelano. The new blood system was called the Kell-Kelano system. Another group was identified after the discovery of the MacLeod phenotype in 1961 by Harvard University medical student Hugh MacLeod.
Blood donation for antigen
In the majority of the world's population, the Kell antigen is negative. That is, this group of proteins is absent. However, it is worthwhile to play it safe and find out your blood type by the Kell-cellano system. Then, in the event of a sharp loss of blood, doctors will know for sure whether the patient can be infused with such proteins or not.
Kell antigen is tested in the laboratory after a special test. For the test, blood is taken on an empty stomach from a vein. Smoking before a blood test for the presence of protein, as with other similar tests, is prohibited.
The reagent is a blood sample in which the Kell antigen is present. Blood for such purposes is taken from donors who are already immunized as a result of blood transfusion.
Abroad, Kell antibodies are produced by certified companies.
Indications for analysis
When red blood cells of a Kell-negative enter the blood of a Kell-positive person, the result is the death of blood cells. Therefore, it is important in the process of preparing for transfusion to find out what type of blood the recipient belongs to - K1, K2 or K0. It is also necessary for pregnant women. With bleeding during childbirth, a conflict of blood between the mother and the child also occurs. As a result, the baby is born already with hemolytic anemia or with hemolytic disease.
Cost
The cost depends on the region where the person lives. The test is simple, it does not take much time. However, reagents have a price, which is included in the cost of analysis. In Moscow, to conduct such an analysis costs from 450 rubles and above.
What happens with a transfusion of another blood group?
So, people with a Kell-positive group can take blood with such a protein. They are universal recipients in this system. But with the K-group, the transfusion procedure is extremely dangerous. If after the first transfusion a person is not particularly affected, his immune system only prepares for an “attack”, forms antigens. When an inappropriate blood group enters the body, an extremely dangerous reaction begins. Red blood cells from donated blood will be killed by the recipient's white blood cells.
Autoimmune hemolytic anemia occurs. This is a very dangerous disease, since it is the red blood cells that carry oxygen. And with a lack of oxygen, all systems and organs suffer.
Do you need Kell-positive donors?
There are very few patients requiring such blood. And therefore, individuals with this antigen cannot become donors.
The Ministry of Health of the Russian Federation is now prohibited from taking whole blood from kell-positive people. Before donating blood, it must be checked for this. Therefore, in Russia there is no risk of post-transfusion complications. But if a person with a Kell-positive group wants to help someone, he has the right to donate blood components such as platelets or plasma.