In addition to "panda blood", there is also "dinosaur blood"?

On TV or in the news, we often see someone's blood type being "panda blood" when they receive a blood transfusion. This type of blood is very rare, and people with the same type of blood are called upon to donate blood.

Sometimes you even see news related to "dinosaur blood".

"Dinosaur blood" news, pictures taken from the Internet

So what exactly are "panda blood" and "dinosaur blood"? How is it different from the ABO blood type we usually talk about? Let's talk about it below.

ABO blood group system

Let’s start with the ABO blood type system that we are most familiar with.

The ABO blood type that we often talk about is related to a doctor named Karl Landsteiner.

In 1900, Landsteiner discovered a phenomenon during an experiment. He found that coagulation occurred after the blood of two patients came into contact with each other.

This strange phenomenon aroused Landsteiner's curiosity, because blood transfusion therapy already existed in his time, but at that time blood transfusion therapy was a bit like taking chances. Sometimes patients would recover quickly after receiving a blood transfusion, but sometimes they would not only fail to recover, but die soon after. Landsteiner hoped to crack the mystery of blood and save more lives.

Soon in 1901, Landsteiner discovered three blood types through experiments: A, B, and O (Landsteiner recorded it as C at the time, and later changed it to O). When he was doing the experiment, there were no AB type blood samples, so AB type blood was also discovered later.

With the ABO blood type system, people have a basis for blood transfusions. It can be said that Landsteiner's discovery saved countless lives, and he also won the 1930 Nobel Prize in Physiology or Medicine.

In fact, ABO blood type involves two types of antigens and antibodies.

Type A blood has A antigens on its red blood cells and B antibodies in its serum. Type B blood, on the other hand, has B antigens on its red blood cells and A antibodies in its serum. Type O blood has neither A antigens nor B antigens on its red blood cells, but both A and B antibodies in its serum. Type AB blood has both A and B antigens on its red blood cells, but neither A nor B antibodies in its serum.

When the same type of antigen and antibody meet, an agglutination reaction will occur. For example, when type A red blood cells enter the body of type B blood, the type B blood's A antibodies will interact with the A antigens on the foreign red blood cells to cause agglutination.

O-type blood does not have AB antigens on its red blood cells, so when O-type blood red blood cells enter the body of people with other blood types, they will not cause agglutination reaction, which is why O-type blood is called universal blood. AB-type blood people have neither A antibodies nor B antibodies in their serum, so they can accept any type of red blood cells.

Rh blood group system

Once you understand ABO blood type, “panda blood” is easy to understand.

The panda blood that people often talk about is related to the Rh blood group system, which is independent of the ABO blood group system. It does not consider the A and B antigen antibodies, but the D antigen.

The blood with D antigen on the red blood cells is Rh positive blood, and the blood without D antigen on the red blood cells is Rh negative blood, which is what we often call "panda blood".

It is called panda blood because it accounts for a small proportion of the population in our country.

According to a study published in 2017, only 0.95% of the Han population has Rh-negative blood, while the Zhuang population has 0.51%. The highest proportion is among the Uyghur population, at 3.33%, and among the Yi population, at 1.25%. Even so, this proportion is not high.

Rh-negative blood ratio of each ethnic group in the study, Image source: References

If we expand the scope to the whole world, there are still considerable differences in the proportion of the population with Rh-negative blood around the world.

For example, in countries such as the United Kingdom, France, and Germany, the proportion of Rh-negative blood can reach 16% to 18%. In the Basque region of Spain, the proportion of Rh-negative blood can reach 28% to 29%.

In Morocco in Africa, the proportion of Rh-negative blood has reached 29%. However, in Indonesia, a survey of more than 48,000 people did not detect Rh-negative blood.

The proportion of Rh-negative blood in people from different European countries, Image source: Reference 2

So, whether Rh-negative blood can be called "panda blood" depends on the place. But the blood type I'm going to talk about next is extremely rare no matter where you put it. This is the so-called "dinosaur blood."

And "dinosaur blood"?

The "dinosaur blood" blood type is related to the Bombay blood group system.

The Bombay blood group system considers whether there is H antigen on the red blood cells. Those without H antigen are called "Bombay blood".

This H antigen has some relationship with the ABO blood type. For example, in the picture below, the dark red hexagon is the H antigen. This antigen is present on the red blood cells of type A, type B, and type O blood, but the H antigen is missing on the red blood cells of Bombay blood.

H antigen and Bombay blood, image source: Wikipedia

As you can guess from the name Bombay blood, this blood type was first discovered in the Mumbai area of ​​India. The proportion of Bombay blood in the population of Mumbai is relatively high, but it is still only one in ten thousand. In Taiwan, China, the proportion of Bombay blood is also relatively high, accounting for about one in eight thousand.

In Europe, its proportion is only one in a million. From these figures, you can see that Bombay blood is rarer than the Rh-negative blood we often say. No wonder it is called "dinosaur blood".

By the way, if people with Bombay blood are tested using the ABO blood group system, they will be tested as type O blood, but in fact, they cannot accept blood transfusions with type O blood and must receive the same Bombay blood.

So if someone with Bombay blood type needs a blood transfusion, the hospital may issue an announcement to the whole society through the Internet, calling on people with the same blood type to help donate blood. Some people may also know about the existence of Bombay blood type through this channel.

References:

[1] Liu J, Zhang S, Wang Q, et al. Frequencies and ethnic distribution of ABO and RhD blood groups in China: a population-based cross-sectional study[J]. BMJ open, 2017, 7(12): e018476.

[2] Weinstock C. It is worthwhile filling in the remaining blank spots for blood group antigen frequencies[J]. Blood Transfusion, 2014, 12(1): 3.

[3] https://www.ncbi.nlm.nih.gov/books/NBK2268/

Author: Dai Li Popular Science Author

Reviewer: Tang Qin, Director of the Science Popularization Department of the Chinese Medical Association

The article is produced by Science Popularization China-Creation Cultivation Program. Please indicate the source when reprinting.