Blood group system

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The red blood cell blood group was developed by K. of Austria in 1900. Discovered by Landsteiner. After cross-mixing each person's red blood cells with other people's serum, he found that some blood agglutination reactions occurred while others did not. He believed that those who agglutinated had an antigen on the red blood cells and an antibody in the serum. If the antigen and antibody have a corresponding specific relationship, an agglutination reaction will occur. If there are A antigens on red blood cells and A antibodies in the serum, agglutination will occur. If the red blood cells lack an antigen or the serum lacks the corresponding antibody, agglutination will not occur. Based on this principle, he discovered people's ABO blood types. Later, he injected red blood cells from different people into rabbits, and produced three types of immune antibodies in the rabbit serum, called M antibodies, N antibodies and P antibodies. Using these three antibodies, three new antigens on red blood cells can be determined. These new antigens have nothing to do with the ABO blood group. They are independently inherited and belong to another blood group system. Moreover, M, N and P are not a system. The blood type genes that control different blood group systems are on different chromosomes. Even if they are on one chromosome, the gene loci of the two systems are far apart and are not linked, so they are inherited independently.

Rh blood type

Rh is the first two letters of the foreign name of Rhesus Macacus. When scientists such as Landsteiner conducted animal experiments in 1940, they discovered that Rh blood group antigens were present on the red blood cells of rhesus monkeys and most humans, hence the name. Anyone with Rh antigen (also known as D antigen) on the red blood cells of human blood is called Rh negative. In this way, people with the four main blood types of red blood cells A, B, O and AB have been divided into two categories: Rh positive and negative. With the continuous research on Rh blood type, it is believed that the Rh blood group system may be the most complex blood group system among red blood cells. The discovery of Rh blood type plays a very important role in guiding blood transfusion work more scientifically, further improving the experimental diagnosis of neonatal hemolytic disease, and maintaining the health of mothers and infants. According to relevant information, the Rh-positive blood type accounts for about 99.7% of the Han people and most ethnic groups in my country, and about 90% for some ethnic minorities. Among some foreign ethnic groups, the number of people with Rh-positive blood type is about 85%. Among the white people in Europe and America, the number of people with Rh-negative blood type is about 15%.

In my country, the number of people with Rh-negative blood type is only three thousandths. to four. The ratio of RH negative type A, type B, type O, and type AB is 3:3:3:1.

RH-negative people cannot receive blood from RH-positive people, because the antigens in RH-positive blood will stimulate RH-negative people to produce RH antibodies. If RH-positive blood is transfused again, it can cause a hemolytic transfusion reaction. However, an RH-positive person can receive blood from an RH-negative person.

There is a special antigen on human red blood cells, which is the same as the antigen on rhesus monkey red blood cells, called "Rh" antigen. Those that contain this antigen are Rh positive, and those that do not contain this antigen are Rh positive. It is Rh negative. There are more Rh-negative people among Caucasians, accounting for 15%. However, the vast majority of the Han population in my country are Rh-positive, and less than 1% are Rh-negative.

[Clinical significance]

1. Prevent hemolytic transfusion reactions caused by the Rh blood group system: If Rh-negative patients are transfused with Rh-positive blood, it can stimulate the body to produce anti-Rh antibodies. When Rh-positive blood is transfused again, hemolytic transfusion reactions will occur. If an Rh-negative woman has given birth to an Rh-positive fetus, hemolysis may also occur when Rh-positive blood is transfused. Therefore, patients and blood donors who need blood transfusions should not only check their ABO blood type, but also do Rh blood type identification to avoid this situation.

2． Neonatal hemolytic disease caused by Rh-positive red blood cells: After a Rh-negative mother gives birth to an Rh-positive fetus, if a certain number of the fetus's red blood cells enter the mother's body, it can stimulate the mother's body to produce anti-Rh-positive antibodies. If the mother becomes pregnant again and gives birth to her second child, During pregnancy, this antibody can pass through the placenta, dissolve and destroy the fetus' red blood cells, causing hemolysis of the newborn.

If a pregnant woman has been transfused with Rh-positive blood, neonatal hemolysis can occur in the first child.

RH blood group system, which contains 6 antigens, namely C, c, D, d, E, and e. All red blood cells containing D antigen are Rh positive, otherwise they are Rh negative. Rh blood type has no natural antibodies, and its antibodies are mostly generated by blood transfusion (Rh-negative people are transfused with Rh-positive blood) or pregnancy (Rh-negative mothers are pregnant with Rh-positive fetuses), which has important clinical significance. Once antibodies are formed, severe transfusion reactions may occur if Rh-positive blood is transfused. Hemolytic disease of the newborn may occur in the pregnancy of an Rh-positive fetus.

Therefore, after an RH-negative woman is transfused with RH-positive blood, antibodies will be produced in the blood, and she will no longer be able to conceive an RH-positive child, otherwise the baby will most likely not survive. In some surviving fetuses, a large amount of bilirubin produced by hemolysis enters the brain cells, causing neonatal central nervous system lesions (called kernicterus. The disability rate of kernicterus is extremely high). Even if they survive, it will affect the intellectual development and movement of the sick children. ability.

If women do not transfuse RH-positive blood, they can give birth to their first child. This is because when the first child is pregnant, the amount of antibodies produced by the pregnant woman is small and not enough to cause fetal disease. If your first child is RH positive, you will not be able to have any more children in the future.

If a man is RH negative, he should not have a second child after giving birth to an RH positive child. However, men will not lose their fertility after transfusion of RH-positive blood.

Note: During blood transfusion, both RH and ABO blood types must be tested

How can people with Rh (-) protect themselves?

Please remember this principle: blood can only be transfused of the same type, that is, patients with type A Rh (-) can only be transfused with type A Rh (-) blood, and patients with type B can only be transfused with type B Rh. (-) blood. If you are sick or require a blood transfusion for surgery, you must inform the doctor of your Rh (-) blood type so that the doctor can contact the city blood station as soon as possible to organize the Rh (-) blood source you need. . If you are an unmarried woman, please plan your family to avoid artificial abortion. If you have a history of miscarriage or blood transfusion, you must go to the blood type room of the blood station for a predictive test for hemolytic disease of the newborn during pregnancy to prevent hemolytic disease of the newborn in the future. occurrence.

Do you know what work the blood group workers have done for you?

Whether the same type of blood can be supplied to Rh (-) patients in an emergency is a life-threatening matter. Blood type workers at blood stations ensure the safety of blood transfusions for every Rh (-) patient. As our responsibility, we have been working tirelessly to screen tens of thousands of blood donors for Rh (-) blood types all year round. Once Rh (-) blood is screened, the bag of blood is immediately marked with a special mark and stored in a 4°C refrigerator for preparation. urgent need.

Is the blood transfusion supply guaranteed for patients with Rh(-)?

Although blood transfusion workers have done their best to prevent problems before they occur, the potential life-threatening danger of Rh(-) patients who may lack the same type of blood in an emergency still exists. In fact, the way to eliminate this trouble is very simple: that is, all Rh(-) people are in the same boat and are in the same boat. While being possible blood recipients at any time, they are also noble blood donors at any time, so that you and all The lives of those with Rh(-) will be protected.

Some blood type antibodies are incomplete antibodies. No agglutination is visible after combining with the corresponding antigen cells. There are antibodies in the serum but they are not easy to detect. In 1945, the antiglobulin test was applied to blood group examination. This test can detect incomplete antibodies. Since then, many blood group antigens have been discovered one after another. Whenever a new antigen is discovered, it is necessary to determine the relationship between this antigen and the already discovered blood types. In this way, several blood group systems are determined on human red blood cells. In addition, there are some antigens that cannot be genetically analyzed either because their frequency in the population is too high or because their frequency of distribution in the population is too low. Before their genetic relationship is clarified, these antigens are temporarily called high-frequency antigens and low-frequency antigens respectively, and their affiliation needs to be further determined.

Different types of blood types

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There are different types of blood. The Austrian pathologist and immunologist Karl. Landsteiner (1868-1943) proposed it in 1902. He once obtained blood samples from himself and five colleagues, synthesized 30 samples, and conducted observational studies. He found that some samples were successfully mixed, while others coagulated (sticked together). He then realized that the situation of each sample was not exactly the same. In the samples of two people, there was a type of "Anti-gen" on the red blood cells. (antigen) substance, he marked it with "A"; the samples of the other two people had another "antigen", which he marked with "B" in alphabetical order; the sample of only one person, A antigen and B antigen None, but there were two types of antibodies in the serum, as did his own blood, so he marked it with "O" (meaning no antigen). Later, he found that a group of people had both A and B antigens in their blood. Antigen, he called it type AB.

Since then, blood has been divided into type A, type B, type AB and type O.

But some scientists predict that there will be types in the future. Type C blood appeared. The earliest human blood type was O, then A, then B, and finally AB. It took millions of years to go from type O to type AB. With the continuous evolution and development of human beings, there will be people with type C blood.