We often see episodes like this in TV dramas: someone suffers heavy bleeding due to a car accident or trauma, the hospital does not have enough blood or cannot find a matching blood source, and immediate family members (parents, children) scramble to donate blood for them
But, Is blood transfusion between immediate family members really reliable? Every June 14th is World Blood Donor Day, so let’s learn about blood today.
Does blood donation cause damage to the body?
- In fact, voluntary blood donation is not harmful to people’s health
Although blood donation is a blood loss process, it has little effect on the loss of blood volume. A 50 kg adult has a total blood volume of about 3500-4000ml, and each donation is 200 or 400ml, which is less than 10% of the total blood volume. WHO believes that for a healthy adult, donating blood does not exceed 13% of his total blood volume and has no adverse effects on the body.
Some people also reported that after donating blood, there will be symptoms such as dizziness and fatigue. Is this normal? Experts say that the vast majority of blood donors will not have adverse reactions after donating blood. However, due to individual differences, a small number of blood donors may experience slight dizziness or even brief fainting, which is a normal physiological response.
In this regard, experts recommend that blood donors drink more water within four hours after donating blood, do not engage in heavy physical or strenuous physical activity on the day of blood donation, do not stay up late, and after a good rest, these conditions will recover quickly.
Can blood be transfused between 2 relatives?
It should be known that in the process of blood transfusion, in addition to the risk of infectious diseases, the recipient must also prevent various adverse reactions during the blood transfusion process.
Transfusion-associated graft-versus-host disease (TA-GVHD) is one of the adverse effects of blood transfusion and one of the most serious complications of blood transfusion.
Because the process of transfusion of allogeneic blood is essentially the process of transplantation of foreign objects, that is, the transplantation of allogeneic cells into the host body to play a role, the transplantation will inevitably be accompanied by a series of immune reactions, and TA-GVHD is a kind of complication with a very high fatality rate. According to domestic and foreign reports, once TA-GVHD occurs during blood transfusion, there is no effective treatment method, and the mortality rate of blood recipients is more than 90%.
The pathogenesis of TA-GVHD is mediated by lymphocytes in the blood, which migrate and proliferate in the patient’s body, thereby attacking and destroying the severe immune response of the patient’s body.
To put it simply, it means that the lymphocytes in the blood of the transfused recipient are mainly reactive, proliferating in large quantities, and frantically attacking the cells and tissues of the recipient. Serious adverse reactions.
The incidence of TA-GVHD, a transfusion complication, was much higher in relatives than in non-relatives. Especially in first-degree relatives, that is, between parents and children, the incidence is 11-21 times higher.
Therefore, in order to avoid complications, blood transfusions between relatives must be avoided to the greatest extent possible.
However, with the continuous development of medical technology, there is special medical equipment that can kill lymphocytes (blood irradiation) in blood, and the treated blood can be safely transfused to one’s immediate family members.
Can saliva be used to test blood type?
- Yes, the right amount of saliva and a certain experiment can get the blood type result.
As early as the early 1930s, foreign scientists discovered that most people’s saliva and other secretions contain the same substance as their own red blood cell ABO blood group antigen – ABH, which can be used as an indicator for personal identification and parental identification through certain tests. One is used in the field of forensic medicine but is rarely used in clinical and routine blood typing.
With the advancement of science and technology and the development of medicine, blood type detection in saliva can now be easily achieved by means of genetic testing: the prosecutor extracts the oral cells shed from the saliva by a certain method, and after amplifying their genetic information, the subjects are tested by specific equipment. The DNA molecular information in the cells can be analyzed and judged, and the blood type of the subject can be obtained.
Mosquitoes love blood type O?
The Shanghai Entomological Museum of the Chinese Academy of Sciences has conducted an experiment on this:
A total of 60 volunteers were selected for this experiment by the Chinese Academy of Sciences. Before the experiment, the blood type of each volunteer was tested, and then the volunteers cleaned their hands with clean water to ensure that their volunteer Hands are free of sweat and odor. During the experiment, the volunteers wore pink plastic gloves uniformly, and a 4 cm opening was opened on the back of each glove. The volunteers put their left and right hands into the mosquito cage twice, and the staff recorded the white and white gloves within 40 seconds of the experiment. The number of Aedes mosquitoes (commonly known as flower-footed mosquitoes) on the backs of volunteers’ hands.
The results showed that under the environment of a temperature of 26℃-28℃ and humidity of 60%, the number of times Aedes albopictus stayed on the back of volunteers’ hands was different, and the order was blood type A ≥ blood type AB > blood type O > B blood type.
On the surface, it seems that blood type B is less likely to attract mosquitoes than blood type O. In fact, the “most mosquito-attracting” type A blood volunteers and the “least mosquito-attracting” type B blood volunteers are favored by mosquitoes only for the average number of times. The difference is half a time, which shows that the odds of attracting mosquitoes are similar for different blood types.
- Therefore, mosquito selection targets are not based on blood type.
Some experts pointed out that mosquitoes looking for prey mainly depends on the strength of the human body’s ability to send “signals” to mosquitoes. The strong “signals” are transmitted through the air, which is helpful for mosquitoes to track the footprints of their prey remotely. A kind of “attractive smell”, and mosquitoes also have a soft spot for prey in dark clothes.
Does blood type 5 predict disease?
As early as 1953, there was research on the correlation between blood group antigen A and the incidence of gastric cancer; In 1960, there were also literature reports on the correlation between ABO blood type and several malignant tumors, indicating that there was indeed some connection between ABO blood type and diseases; People with neuritis, acute myelitis, and periodic paralysis are mostly people with blood type A; some studies have shown that people with blood type A are relatively susceptible to new coronary pneumonia; people with blood type B are more susceptible to pathogenic pathogens; people with blood type O are esophageal cancer, Cardia cancer, prostate cancer incidence is higher, but O blood type people suffering from vascular embolism and atherosclerosis lower probability.
Although there are more and more studies on the correlation between blood type and disease, most of them stay on the discussion of statistical results, and there is no discussion on the relevant mechanism. In fact, there are many factors that affect the occurrence of diseases, and blood type may only be one of the relevant factors.
What are the rare ischemic types?
Since Karl Landsteiner discovered the ABO blood group system in 1900, the MNS and P blood group systems in 1927, and the application of indirect antiglobulin technology in 1945, humans have successively discovered more red blood cells blood group systems.
With the development and application of molecular biology technology, human beings have discovered 30 red blood cell blood group systems by 2010. With the rapid development of genome sequencing technology, five new red blood cell blood group systems have been officially named in 2020 alone. As of June 2021, a total of 43 red blood cell blood group systems have been identified.
Speaking of rare blood types, there are actually many rarer blood types besides Rh-negative blood (panda blood)! For example, as early as 1952, the extremely rare “Mumbai blood type” was discovered for the first time in Mumbai, India. The proportion of people with this blood type in our country is only 1 in 100,000. So far, there are only about 30 cases in our country. Reports related to this blood type.
People with Bombay blood type do not have H antigen in their bodies. Regardless of whether they have alleles of A and B blood types, their A antigen and B antigen cannot be synthesized. People with this blood type cannot accept blood transfusions from any non-Mumbai blood type individuals.
Is “panda blood” hereditary? Does it affect health?
Rh-negative blood is also known as “panda blood” in China because of its rarity.
Rh blood group and ABO blood group are two blood group systems closely related to clinical blood transfusion. If a person’s red blood cells have antigens on them, then it is positive blood, if there is no antigen, then it is negative blood, which is what we call Rh-negative blood.
“The distribution of Rh-negative blood is closely related to ethnicity. For example, the proportion of Rh-negative blood in Europe is about 15%, but in China’s Han population, it only accounts for 3/1,000. Rh-negative blood is also divided into Rh-negative. Type A, Rh-negative type B, Rh-negative type O, and Rh-negative type AB, the ratio is about 3:3:3:1. That is to say, people with Rh-negative type AB are rare among the rare, accounting for a proportion of the population of Less than 1 in 1,000.
So, is Rh-negative blood hereditary? Does it affect health? Experts say that Rh-negative blood is hereditary, but it will not affect physical health. It should be noted that under normal circumstances, Rh-negative people with Rh-positive blood cannot be accepted. Rh-negative pregnant and lying-in women must explain their blood type to the doctor in advance, and conduct regular antibody screening during perinatal health care.
There are still many unknown things about blood waiting for human beings to explore. Because of its particularity and complexity, it still cannot be artificially manufactured, and it can only rely on free donations from healthy people of appropriate age!
June 14, 2022, is the 19th World Blood Donor Day. I hope that you who read the popular science articles can take your precious time to be brave. Let’s go to the blood donation car! Let’s be a “big hero” that saves the lives of others!