Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Enzymes open new path to universal donor blood

dtu.dk

Post reply on HN
Print view View original

11–20 of 34 posts

Re: Enzymes open new path to universal donor blood

#11

Post by XorNot »

Terr_ wrote: post #6
TSP00N3 wrote: post #4

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.redcrossblo…

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.

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.

Re: Enzymes open new path to universal donor blood

#12

Post by [deleted] »

Buttons840 wrote: post #9
HPsquared wrote: post #7

Earlier quoted context omitted.

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 forei…

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…

[deleted]

Re: Enzymes open new path to universal donor blood

#13

Post by Terr_ »

smegger001 wrote: post #10
HPsquared wrote: post #7

Earlier quoted context omitted.

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 forei…

there is also the HH blood group that will react negatively to O type blood as well as A and B.

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/

Re: Enzymes open new path to universal donor blood

#14

Post by Terr_ »

Terr_ wrote: post #13
smegger001 wrote: post #10

Earlier quoted context omitted.

there is also the HH blood group that will react negatively to O type blood as well as A and B.

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,…

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".

Re: Enzymes open new path to universal donor blood

#15

Post by blendergeek »

Buttons840 wrote: post #9
HPsquared wrote: post #7

Earlier quoted context omitted.

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 forei…

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…

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.

Re: Enzymes open new path to universal donor blood

#16

Post by linooma_ »

Buttons840 wrote: post #9
HPsquared wrote: post #7

Earlier quoted context omitted.

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 forei…

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…

> I think O is recessive

Strangely, O is very common.

Re: Enzymes open new path to universal donor blood

#17

Post by riffraff »

linooma_ wrote: post #16
Buttons840 wrote: post #9

Earlier quoted context omitted.

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…

> I think O is recessive Strangely, O is very common.

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.

Re: Enzymes open new path to universal donor blood

#18

Post by Sn0wCoder »

Terr_ wrote: post #13
smegger001 wrote: post #10

Earlier quoted context omitted.

there is also the HH blood group that will react negatively to O type blood as well as A and B.

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,…

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.

Re: Enzymes open new path to universal donor blood

#20

Post by thaumasiotes »

linooma_ wrote: post #16
Buttons840 wrote: post #9

Earlier quoted context omitted.

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…

> I think O is recessive Strangely, O is very common.

What's the strange part? "Recessive" and "common" are different concerns.

Having five fingers per hand is recessive too.

Post reply on HN