Enzymes open new path to universal donor blood
dtu.dk
dtu.dk
"For the first time, the new enzyme cocktails not only remove the well-described A and B antigens, but also extended variants previously not recognized as problematic for transfusion safety. We are close to being able to produce universal blood from group B donors, while there is still work to be done to convert the more complex group A blood. Our focus is now to investigate in detail if there are additional obstacles and how we can improve our enzymes to reach the ultimate goal of universal blood production," says Professor Maher Abou Hachem, who is the study leader at DTU and one of the senior scientists behind the discovery.
Anyways, can someone please explain how positive/negative plays a factor here? Rh +/- is mentioned once in the article but not discussed as far as being a donor. I was always told O- is the universal red cell donor [1]. Can anyone help explain is this enzyme fixes the +/- component in addition to the ABO component? Thanks!
[1] https://www.redcrossblood.org/donate-blood/blood-types.html
Since there are different classes of bio-molecules, proteins may need different techniques to remove, alter, or cover them up.
If we do find such techniques, they may have much broader applications in immunology.
The A/B/AB/O is basically having only A, only B, both, or neither. And the +/- is whether you have the "Rhesus" component.
The basic rule is that you can't introduce new components to a person who doesn't have them in their system, and will be treated as foreign contaminants.
So someone with all three components already (AB+) can take any blood because their system already is used to all three components.
A person with none of the components in their system (O-) would have an allergic reaction to any of the three components being introduced. On the other hand their blood is safe to donate to anyone else as it won't introduce any "unexpected components" to a recipient.
EDIT: ah, I see - article doesn't mention Rhesus. I guess it can convert AB- to O-, or AB+ to O+.
A is really AO (if we're being verbose). B is BO, AB is AB, O is OO. Each parent passes one of them on. So, a A dad and O mom would mix (being verbose again) AO and OO, and thus the child might be AO or OO, A or O.
The + or - is for an independent "Rhesus" component, as you say. Not sure how this passes through the genes. This is all like high school level knowledge, so maybe someone can share more if they want.
My dad had surgery and some paperwork we received said that he had AB blood. It became a family joke because me and my siblings are all O blood type. If my dad really did have AB blood then we are not his children. The hospital later confirmed it was a mistake.
A can be either AA or AO and B can be either BB or BO.
AB is always AB like you said and O is always OO.
Strangely, O is very common.
Of course there's crackpot theories (aliens!) too.
Having five fingers per hand is recessive too.
Fascinating, and true.
Which engenders speculation about how the world would be different if we counted in base-12. Obvious advantages to convenient divisibility aside.
Asking what the historical difference would be if we wrote our numbers in base 12 instead of, variously, 10, 12, or 20 (all historically common, and 60 is prominent too), is like asking what the historical difference would be if we wrote our words in Greek letters instead of Roman letters.
Note that it was common for people to count dozens on their hands; each hand has four non-thumb fingers with three knuckles each.
My point is that if base-12 was biologically natural, instead of more effortfully useful, there would be many differences in the way we do things -- although of course we would be mostly unaware of them, as a fish in water.
There would be no metric-vs-imperial units dichotomy, for example. (EDIT: Or at least the conflict would be different and likely lesser, ergo easier to switch)
NASA probably wouldn't have lost the $327MM Mars Climate Orbiter. And it wouldn't have cost $327MM in the first place.
In some cases, unit sizes would be different. That's the easy case. But in counting systems, 100 of some atomic thing would be 44% more than it is today. 1000 would be 73% more. 1MM would be almost triple. Given the attachment people have to round numbers, this would have implications. Some things would be bigger. Other things would be considered in different increments.
It's interesting. Not profound.
No, they wouldn't. This would be a very minor effect, because the primary determinant of sizes and amounts is how big you need something to be, or how much of it you need.
Instead, you'd see the same thing we already do see: contexts in which an existing unit was difficult to work with would be given their own units of a more convenient size. Consider how horses are measured in increments of four inches, or how soft drinks are sold in unit sizes of 12 ounces, 20 ounces, and 67.6 ounces.
The units aren't called that, of course; those sizes are "one can", "one bottle", and "two liters".
It's likely that in a base-12 world, we'd still have "100" "cents" in a dollar. But there would be 144 (base-10) of them. That alone is interesting! But it's fine, because the collation is geometric, but the cent unit size is arbitrary.
Similarly, who knows or cares how many base-12 fluid ounces would be in a food product -- the collation (packaging) would be humanely-sized regardless.
But some units are not arbitrary, or conveniently divisible, and some collations still tend toward geometric affinity. Humans have their idiosyncrasies.
Would there be 10 base-10, or 10 base-12 amendments in the US Bill of Rights? What would the additional two amendments be?
Would there be 10 base-10, or 10 base-12 commandments in the Hebrew Bible?
Would we talk about a US president's first 100 base-10, or 100 base-12 days? Would the extra 44 days matter?
Again, none of this is profound. But if you think it isn't interesting, we'll just have to disagree.
This is a case where there's no difference. Right now, Wikipedia's page on the Ten Commandments notes 15 different commandments. (Actually, 16, but two of those are "thou shalt not covet thy neighbor's house" and "thou shalt not desire thy neighbor's house", and Wikipedia knows of no tradition that thinks of those two as separate commandments.) Here it is obvious that the number of commandments is significant, at 10, and the content of the commandments is significant, but unrelated to the number. If you want 12 commandments instead, it's sufficient to renumber the existing 15 commandments, and this is clearly how the problem has been approached historically.
The same thing applies to the Bill of Rights; there are a lot more than 10 enumerated rights, but they're bundled into 10 amendments.
> Would we talk about a US president's first 100 base-10, or 100 base-12 days? Would the extra 44 days matter?
This might make a difference; 144 days is close enough to half a year that you might just mark the half year and not bother with the 144 days. Or you might mark the quarter-year, which is almost 100 days.
Since H is also a building-block needed for A and B to show up, it makes for fun medical-mystery plots, where a child's blood-type seems to be O and doesn't match their parents, but in reality they did get parental A/B/AB genes that just aren't able to express because each parent contributed a nonfunctional H-allele.
Instead patients would have a "blood code" that indicates the tested presence or absence of phenotype cellular features, and any feature not listed would be considered "not yet known, do a test if it might be important."
For example, today's AB- would become +HAB-R for "has H,A,B lacks Rhesus factor." Similarly, O+ would become +HR-AB, and the super rare mutation we were just talking about would be either +R-HAB or -HABR.
Then when we eventually discover a yet-another factor X... Well, yes, your code wouldn't be constant throughout your life, because after an X-test it would gain either a +X or -X... However the upshot is that it eliminates weird implicit guessing games, and medical professionals will "know what they don't know".
That's already the way A, B, and Rhesus factor work. The abbreviation for Rhesus factor is "+", but the formal terminology is "Rh+". I would have expected "H-" by analogy.
No, it isn't: The current ABO system is incapable of expressing "null" data (e.g. "we don't know if B antigens are present or not") and relies on implicit "no marking means false" assumption, which becomes a problem if a new/newly-important antigen feature is discovered, or if a new variation of an existing antigen is found.
For example, suppose we discover a new type Z, which is a membrane-sugar just like A and B, and logically ought to be encoded the same way. It exists in a 50/50 ratio in every existing blood-group, and it finally explains some rare but fatal transfusion problems.
Now some unconscious patient arrives at the emergency room with a wristband saying "AB+". Does that string mean they were tested for Z already, and it was absent, or does it mean there no data about whether Z is present or not? Nobody knows! Worse, if you do a test and discover no Z, then you write the same thing and have the same problem later, all because of the mistake of encoding "false" as an empty string.
Now you might say "Forget the ABO crap, require Z+ or Z- to appear as a separate item", I'll say: "I totally agree, but let's remove the ABO crap and encode all the antigens the same way to make it logically consistent and clear."
> I would have expected "H-" by analogy.
If you're thinking of another section like "A Rh+ H-", then that's close to what I'm proposing, except that it hasn't fixed the historical ambiguities of O/A/AB.
If you fix it to make things explicit and consistent, it becomes "A+ B- Rh+ H- ", and if you shorten Rh to R and group similar things together... that leads to codes like +R-HAB or -ABH+R, which are (ordering aside) what I just proposed.
Thank you for the information as I always love learning more from the comments than the articles.
https://ashpublications.org/blood/article/115/23/4635/27755/...