Probably, absolutely everyone knows that there are many different components in the blood. In addition to the direct formed elements, nutrients and other parts carried by the blood, it is possible to find special proteins in it, which vary from one person to another person. And if the proteins responsible for the blood group and the Rh factor have been known for a long time, then a blood test for Kell antigen began to be massively carried out no earlier than the end of the 2000s.
Antigen Description
To find out, in general, that these are “antigens of the Kell system”, it is necessary to explain what antigens are in general. And how do they get into the blood.
An antigen is a protein molecule that is recognized in one way or another by the immune system. Most often, this term is used in relation to any foreign proteins that need to be removed from the body. But antigens are present in the body in large quantities. In particular, the Kell antigen is present on the surface of blood cells of red blood cells. And is an integral part of the body. Most people do not have a kell factor in their blood. But about 10% of people are still kell-positive.
In view of the foregoing, the definition of Kell antigen will be as follows: this is a protein system located on the surface of red blood cell cells in 10% of people.
Why analysis is important
Until a certain point, blood tests for Kell antigen were not done at all, since few knew about its existence and effect. However, in medical practice there have occasionally been cases where, it would seem, blood suitable for transfusion still evoked an immune response in the recipient, as if transfusion of absolutely foreign blood was carried out. As a result of several such transfusions, even hemolysis (destruction of blood cells) is possible with antibodies that are produced against Kell antigens that enter the bloodstream.
It is also important to do this analysis if the couple is planning children. The effect of Kell antigen on gestation and birth is approximately similar to the influence of the Rh factor. That is, during pregnancy, a Kell-negative mother, a Kell-positive child, the mother may form an immune response to "extraneous" proteins.
Also associated with this protein system are some congenital diseases of infants, such as hemolytic disease of the newborn and autoimmune hemolytic anemia.
An unusual combination of kell-positivity with the ability to feel the bitter taste of thiourea can be considered as special relationships. It is believed that people who can recognize this taste sensation also have Kell blood factors. This is due to the fact that the presence of the Kell system in the blood and taste buds that recognize the bitterness of thiourea are located in adjacent loci of the same chromosome.
Discovery story
This group of antigens was first discovered back in 1945 in the blood of a pregnant woman, Mrs. Kellacher. However, only antibodies of the same type were present in her blood, further discoveries in this direction were made shortly afterwards. In particular, it was documented that the second described woman with similar antigens was a certain Mrs. Cellano, who was also a pregnant woman. Later, these antigens were studied in more detail, and people with Kell-negative blood were also studied. Harvard student Hugh MacLeod discovered a particular abnormality in blood protein, which was later named after him.
Macleod phenotype
May also be called Macleod's syndrome. It consists in an anomaly associated with the X chromosome, which makes the detection of the Kell system in the laboratory as difficult as possible. This mutation is a gene that encodes a protein, which, apparently, is responsible for the correct presentation of Kell antigens on red blood cells.
Preparation for analysis and its implementation
As with most such tests, the Kell factor test is performed on an empty stomach. It is important to wait at least 3 hours from the last meal before donating blood for analysis. It is allowed to drink non-carbonated mineral water.
Identification of the Kell factor is carried out by a qualitative method. This means that the results of the analysis can show only the absence or the presence of the desired antigen. It is believed that most people do not have it in their blood.
It should be recalled that the presence of the Kell factor in itself is not a reason to worry about anything. If a Kell-positive person wants to become a donor, he is given the opportunity to donate blood to plasma or platelets, which is also important for medicine. And future parents should familiarize themselves with the results of the analysis in order to have accurate information about all the possible risks for both the mother and her unborn child. One way or another, one should approach analysis as one more opportunity to find out information about oneself and one's body, and be able to prepare for any unexpectedness associated with this.