[HN Gopher] Enzymes open new path to universal donor blood
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Enzymes open new path to universal donor blood
Author : gnabgib
Score : 136 points
Date : 2024-04-30 16:41 UTC (1 days ago)
(HTM) web link (www.dtu.dk)
(TXT) w3m dump (www.dtu.dk)
| ashvardanian wrote:
| Made my day! Progress worth living for!
| downrightmike wrote:
| Very cool stuff!
|
| "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.
| bayouborne wrote:
| Cinemax's excellent 'The Knick' (about a chief surgeon at the
| Knickerbocker Hospital in 1900's New York) had a gut-wrenching
| one or two episode arc about efforts to refine transfusion
| techniques and why the team kept seemingly randomly ending up
| w/dead patients because no one had yet understood Rhesus factor
| proteins.
| TSP00N3 wrote:
| Long time listener, first time caller (finally made a HN
| account)..
|
| 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
| Terr_ wrote:
| That's probably a separate and harder problem from this: The A
| and B antigens refer to the presence of carbohydrates extending
| from the cell membrane, whereas Rh factor + refers to the
| presence of a protein.
|
| 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.
| XorNot wrote:
| Rhesus factor is a lot more forgiving though: i.e. in a
| crisis you can transfuse rhesus positive blood to a rhesus
| negative person successfully since the sensitization doesn't
| emerge immediately.
| HPsquared wrote:
| There are three components that can cause problems with
| transfusions: "A", "B" and "Rhesus". A person can have any
| combination of those three (8 combinations).
|
| 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+.
| Buttons840 wrote:
| I _think_ O is recessive (if I remember from high school
| correctly).
|
| 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.
| blendergeek wrote:
| You mostly remember correctly. One small nitpicko on the
| genetics (based on my high school biology)
|
| 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.
| linooma_ wrote:
| > I think O is recessive
|
| Strangely, O is very common.
| riffraff wrote:
| I seem to remember the explanation is that A and B are
| somewhat recent mutations in evolutionary terms, they
| simply have not had time to cancel out 0 yet.
|
| Of course there's crackpot theories (aliens!) too.
| thaumasiotes wrote:
| What's the strange part? "Recessive" and "common" are
| different concerns.
|
| Having five fingers per hand is recessive too.
| quesera wrote:
| > _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.
| smegger001 wrote:
| there is also the HH blood group that will react negatively
| to O type blood as well as A and B.
| Terr_ wrote:
| That naming is a little confusing, because if you say
| "blood group "A" or "B", that indicates the _presence_ of A
| and B antigen structures, however "blood group H" means a
| _lack_ of H. (Since almost everybody has H, it was
| discovered much later.)
|
| 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.
|
| https://www.ncbi.nlm.nih.gov/books/NBK2268/
| Terr_ wrote:
| P.S. IANAPhlebotomist, but if I could wave a wand to
| change the nomenclature, I'd make it stop relying on an
| implicit "nothing" state that keeps changing under us as
| we discover new features that are either usually-present
| or usually-absent.
|
| 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".
| thaumasiotes wrote:
| > For example, today's AB- would become +HAB-R for "has
| H,A,B lacks Rhesus factor."
|
| 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.
| Terr_ wrote:
| > That's already the way A, B, and Rhesus factor work.
|
| 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.
| Sn0wCoder wrote:
| I have never heard of the H-allele. Not sure if
| @Buttons840 has seen this but "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."
|
| Thank you for the information as I always love learning
| more from the comments than the articles.
| jorvi wrote:
| Also important to note that blood plasma is the reverse. So
| AB+ is universal plasma donor, and O- universal plasma
| receiver!
| noah_buddy wrote:
| Similar news recently about opening up the doors to less
| compatible donors for PBSC or bone marrow.
| Purplehermann wrote:
| Link?
| gorkish wrote:
| Enzymes catalysts and molecular scale physical chemistry is
| really kicking ass recently. Seems that we are tipping over the
| knife edge of well and truly cracking the code!
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