Why do we have different blood types?

Our blood is one of the essential elements in vampire mythology , but it is not just the covetable viscous liquid desired by a vampire in a horror story ; it is a vital element in our body, it runs throughout our body: in the heart , in the brain , even in the little toe; there is no corner of our body that is not related to it.

The blood is dark red when it circulates through the veins and bright red inside the arteries ; Blood is made up of plasma and cells, one of these cells being red blood cells or erythrocytes .

The main function of erythrocytes is to oxygenate the blood through hemoglobin, which captures oxygen and releases it in the tissues; it also recovers carbon dioxide and removes it from our body through the lungs.

Erythrocytes are cells without a nucleus which, in addition to oxygenating our blood, are a fundamental key to determining what blood type we are. Like all cells, red blood cells have a membrane around them, which has different sugars or carbohydrates inside or outside.

what blood type are you? It is estimated that 90% of the Mexican population is O positive.

We are different in each cell

There are currently 33 studied blood systems , but there are more because many sets of sugars or antigens are located in the membrane . The erythrocyte blood groups are derived from the systems . They all have the same importance, but the best known are the ABO and the RH due to their medical importance.

Hematologists explain that having different blood types is due to genetics , it depends on the information inherited from our parents, from them we acquire genes that express enzymes, these enzymes produce sugars around the erythrocyte and it is these sugars that determine the blood type of each person.

For example, if you have an enzyme that produces the carbohydrate N-acetylgalactosamine , it will be attached to the membrane and therefore you express type A antigens. If you inherited an enzyme that attaches Galactosamine to your erythrocytes, you have type B antigens. There is a possibility of inheriting both sugars, being AB antigen. It is also possible not to have inherited any of those sugars, that is to say to be zero, but it is known as the O antigen.

However, by having a certain blood type you will generate "natural" antibodies against what is unknown to your body, that is, if it is A you will have anti-B, type B have anti-A, AB do not have antibodies, but O are anti-A, anti-B and anti-AB. This is important in blood transfusions because they must be compatible with each other. Type A's can receive blood from A and O, B's are compatible with B and O, AB's are compatible with A, B and O. But for O's, you can only donate another O.

But the explanation is not so short, another blood system is also involved, the Rh system, this is determined by the membrane, but this time by a transmembrane protein , that is, it is inside the membrane. If we have that protein we are +Rh, otherwise we are -Rh.

Then, blood transfusions are no longer simple, in addition to the compatibility of the ABO system, the Rh system is added where the positives can receive blood from the negatives and positives, but the negatives only from the negatives.

Incompatible even in the blood

The importance of the blood systems lies in the very life of the people, if the blood transfusion is done with incompatible blood there may be a destruction of the transfused red blood cells and remember, the erythrocytes are responsible for carrying oxygen to our lungs, so which can cause death.

It is also important to take into account the blood type of pregnant women and their fetuses, since they can be incompatible and during childbirth when there is an exchange of blood fluids, this would cause hemolysis in the newborn, that is, destruction of the erythrocytes and a anemia due to lack of erythrocytes.

In the case of pregnant women with O Rh negative blood, the situation is delicate, with the first incompatible child, that is, with positive Rh nothing happens, but the mother's body creates antibodies and stores them in memory; the problem is when she and the second fetus are also not compatible.

"The mother's body already has antibodies in memory against Rh and will destroy the baby's erythrocytes, causing death by destruction of red blood cells: hemolysis," explains Dr. Adriana González Villalva from the Department of Cellular and Tissue Biology of the UNAM .

But thanks to the advancement of science there is a vaccine: anti-D immunoglobulin , which stops the mother's immune response , the function of this vaccine is to prevent antibodies from being stored in the memory, but it is necessary to apply it in each pregnancy, during the first 72 hours after delivery.

Related diseases

According to the most recent medical book specialized in Applications and Practice of Transfusion Medicine , it was determined through rigorous studies that the inheritance of ABO antigens is weakly associated with predisposition to certain diseases.

Type A individuals have a 1.2 times higher risk than type B and O to suffer from disorders of the digestive system such as gastric or colon carcinoma . Type O people have a predisposition 1.4 times higher than the rest of the blood types to suffer peptic ulcer and those of type B have a higher risk of suffering infections by Streptococcus pneumoniae and Escherichia coli.

“But it does not mean that if you are type A, you will necessarily get gastric carcinoma, rather, you are above the normal percentage to suffer from it,” explains Dr. Eva Delia Calderón Garcidueñas of the High Specialty Naval General Hospital and professor at the Faculty of Chemistry from the National Autonomous University of Mexico, Mexico.

Knowing our blood type is very important, it is vital for a blood transfusion, for a pregnancy, even to take care of our health. From now on you will no longer see the normal flow of blood through your veins, you will be aware of the incredible function of each cell that runs through your blood.