Hi everyone,
It has been a rough week for me so I need to take a step back from blogging last week to resolve my issues and thank god, I did it. Now with every single distraction has gone, it's time for me to write something. I haven't been consistent much lately and I will try to do so for the next few days. In this article, we are going to talk about blood (just a little about it) and how current research has found that enzymes produced by our gut's bacteria have the potential to mediate blood type changes thus eliminating the needs to ask for a specific blood type in the future. Sound too good to be true but let's get on it anyway.
I'm not going to rumble regarding types of blood cells and the function of each but I do want to make a quick note about how blood can be differentiated by proteins or sugars located at its surface called antigens. Different types of blood exhibit different kind of antigens which is usually rejected by an individual who has a different kind of blood in a process called the transfusion reaction. Before the time we knew about this antigen, people thought that all of us (including other mammals) have the same exact blood type thus it would be reasonable to transfuse it if someone needs it.
I mean, we can imagine people were getting transfused with cow's blood and often they would die from an adverse transfusion reaction. It is not until the 1900s that all of us realised that we belong in a different blood group according to the available antigens on the surface of the red blood cell. Foreign antigens would always be greeted by the immune system as a hostile target and compared to self-antigen (any antigen which originated from the body), the immune couldn't care much about it.
To make it simple, we have 4 major blood groups which are A, B, AB and O. It is simply named after the type of antigen presented on the surface of the red blood cell. A host will have a type of antibodies which will target antigens which are not presented on the surface of the red blood cell of the host. I know it sounds tricky but it simply means that for those who were in the A blood group, they would have type-A antigen along with antibodies for type-B antigens. Any transfusion of blood which contains type B antigens into people who have type-A red blood cells will cause an adverse reaction manifested as signs and symptoms which is often called as the transfusion reaction.
Although it sounds grim, nowadays, with an advent of technologies that could screen in details what kind of blood we were having, all of those nasty side effects of blood transfusion can be avoided. Rhesus factor is one of the main concern of blood transfusion and often overlooked in the past due to the fact that we don't have all kind of necessary equipment to know whether an individual is rhesus positive or rhesus negative.
Unlike the ABO antigens, rhesus antigens are made up of proteins. It's called as the D antigen and usually presented as either positive or negative at the end of our blood type. For example, A+ means you belong to blood group A with rhesus antigens while O- means you don't have rhesus antigens; note that people who were negative for rhesus proteins have rhesus antibodies so it is crucial for us to know before a blood transfusion whether the patient is rhesus positive or negative. Otherwise, people could experience a transfusion reaction even with the same blood type.
How Common Is Each Blood Type?
Although we know the fact that the commonest blood type would vary among populations, in general, the most common blood type is the blood type O while the least common is the blood type AB. According to a study conducted by Garraty G. in 2004, Hispanic people constitute the highest number of individual with blood type O followed by North American and black non-Hispanic people. It kinda gives us the advantage since blood type O can be considered as the universal donor, as they have neither A nor B antigen making it plausible to transfuse into people with any kind of blood type. It is worth noting that, people with blood type O can only receive blood from people who are in the same group as they possessed both the A and B antibodies.
If you have type A blood group and currently need an urgent transfusion while being admitted in a hospital somewhere in the Central or Eastern Europe, then you are lucky because blood type A is the commonest blood group in those regions. It's truly remarkable that almost 60% of the total population have type A blood group and among them, the minor race called the Blackfoot Indians has 80% people who can be classified in the type A blood group.
In Asia, blood type B is the commonest type, constitute approximately 25% of the total population. It's not that high and generally, blood type B is just a step away from AB, the least common blood type in the world. You might be common if you were having blood type B and were living in Asia but if you move to America or Europe, you are one out of 10% of the minority who were having a type B blood type.
What about AB? Is it the rarest blood type in the world. Well, it certainly is the least common but not the rarest. The rarest blood type in the world is called as the Bombay blood type. Apart from having the ABO antigen, each and every of the blood cell is defined by the specific antigen called the H antigen. The function of this H antigen is poorly understood but generally, all blood type except for Bombay have H antigen scattered around the surface along with each respective antigens. Bombay blood cell doesn't have any of those antigen. They have, however, antibodies to all of the antigens; you name it A, B, H. This means that people with Bombay blood type can be a universal donor, but it can't receive a blood transfusion from any people other than people with Bombay blood type.
Unlike people who were with O blood type, there are only 1 out of 250,000 people who were having a Bombay blood type which means they are pretty rare. Even if they can donate their blood to other people, if things go wrong, they can be potentially screwed. It's difficult but people with Bombay blood type should have some safety measures to ensure people would know just in case if they were involved in any kind of emergency like a tattoo, card or necklace or something.
Gut Bacteria And Blood Type
It has been found, recently, that gut bacteria would have the capability of removing the sugar-made antigen on the surface of the red blood cell, converting them into O blood type from any available blood type. This is a particularly important finding if it is valid as people have been itching to get their hands on the O blood type since it is considered as the universal donor. Removing the antigen could spare us a lot of time from dealing with transfusion reaction potentially cause by the conflicting antigens presented on the donor's blood.
Even though the number of people with blood type O is considered the highest around the globe, that particular blood type is in high demand due to its capability of avoiding the adverse effect that might have caused by the immune system and there are not so many people with O blood type who were donating theirs. The finding could have been accidental as up until now, researchers were still confused regarding the exact enzyme which could have the potential of wiping all kind of surface antigens without damaging the structural integrity of the red blood cells.
On August 20th, 2018, Withers made a presentation claiming that he and his team discovered a potential enzyme which could have been used to wipe out A and B antigen transforming the blood into the O blood type. This is the perks provided by the enzyme produced by the gut bacteria as the actual purpose for it is to aid bacteria plucked mucins of the digestive tract. What a coincidence, the structure of mucin almost resembles the structure of both A and B antigen of the red blood cells. For now, it seems the enzyme can remove A antigen much more effectively than the B antigen but I'm sure with some more research, we might be able to find some kind of factors that would increase the efficiency of those enzymes in wiping both of the antigen to create a universal donor blood for the sake of mankind. Who knows, someday, Bombay blood can be synthesised too? That's what I love about science. It evolved every single day.
References: [1], [2], [3], [4], [5]
All images were taken from Pixabay
Images: [1], [2], [3], [4], [5], [6]
This is not the first time this kind of enzyme has been discovered though. In 2015 the same group made a similar enzyme by directed evolution. But this is cool esp the fact that they did this from gut bacteria. Wonder how does the two compare and if they iare going to further modify the enzyme for increasing the efficiency, yet further. This is pretty cool work by this lab.
I agree. The work done by the team was pretty much cool although I'm not sure whether it is novel or not. Thanks for your feedback.
Glad to see you are back. Reading through your article, if scientists were, in fact, correct in their assumption, we can potentially create any blood types we want as long as we know how to use the enzyme.
That is correct. Think about how much we can do for the world if we can convert all kind of blood to a universal donor type. O- can be restocked with A- or B- by simply deleting the sugar antigen responsible for labelling them A or B.