[paul.fr]

Do transplanted organs have memories from their host?

[chris]

Well they do carry a genetic "memory" of where they've come from of course; what I mean by that is that inheritance imprints certain patterns of gene expression on an individual. This will be mirrored in the transplanted organ.

But organs will not, as some wacky people allege, enable a recipient to in some way plug into their donors life experiences and memories. That's just a load of old rubbish.

Chris

[kdlynn]

unless of course it's a brain transplant

[kdlynn]

just kidding i know they don't do that

[another_someone]

Are you referring to this discussion: http://www.thenakedscientists.com/forum/index.php?topic=7264.msg76018#msg76018 ?

[paul.fr]

Are you referring to this discussion: http://www.thenakedscientists.com/forum/index.php?topic=7264.msg76018#msg76018 ?

No, I'm not thinking that a heart from a donor would in some way influence the recipient. I was thinking more along the lines of say a skin transplant. if the donor had eczema would the recipient have it, facial ticks and such.

[chris]

That's a good point Paul, because if you think about cystic fibrosis, part of the reason why a lung transplant works in people with this disease is that the donor lung(s) all carry a healthy copy of the CF gene, so the tissue is free from the disease. The rest of the body's cells, however, continue to carry the abnormal gene.

In respect of eczema, however, that's a bit different for two main reasons:

1) Eczema occurs when the immune system produces too much IgE antibody. This arrives via the bloodstream and glues itself to the surface of histamine-containing "mast" cells in the dermis. When antigens against which the ezcema sufferer is reactive are presented to the IgE it activates the mast cell, leading to the production of histamine and an itchy reaction.

Therefore, in a new host with normal levels of IgE and no adverse reaction to the antigen that the skin donor reacted to, there won't be the same IgE-activity and therefore no histamine release and therefore no eczema.

2) In an organ recipient patients are usually on immunosuppression, so mild allergic conditions like hayfever and eczema would be reduced / quenched anyway.

Chris

[kdlynn]

wait a second... lung transplants can help cystic fibrosis patients? is that only done in very late stages? my cousin has it and i've never heard that before. just curious

[kdlynn]

wouldn't their body reject the lung because it does have the normal gene? i thought that was the problem with actually finding the cure. their bodies won't accept the correct gene

[Negin -(Universe)]

why wouldn't the body accept the correct gene? I've learnt that the only reason our bodies reject foreign bodies is due to us having different 'self cell' recognising protein on our cell's surface, so we only recognise those cells with the specific antigens as self everything else is non-self, so thats why doctors suppress the immune system to disable the body's cell recognition. so i don't see any reason for a cell to reject a correct gene, i mean after all if person can then breath normally after the transplant the body will 'feel' much better as a whole.

[chris]

That's right. Any protein which is different to one that we already find in the body is viewed as hostile and foreign by the immune system, which raises a response against it.

A good example of this is in people with the bleeding disorder haemophilia, which is caused by a lack of blood clotting factor VIII (and more rarely factor IX). They can be treated by injecting the missing blood factor, but because they lack this protein normally, eventually the immune system mounts a response against it in the form of circulating antibodies that bind to it and prevent it from working. This is known as an inhibitor and affects up to 40% of haemophiliacs. The result is that patients need to use much bigger doses of factor VIII to achieve the same effects and in some cases their treatment may even stop working.

In the case of cystic fibrosis, a lung transplant is offered when a patient's own lung function has deteriorated to the extent that they cannot survive. The transplant works for two reasons. 1) The new lungs are healthy and hence better at oxygenating the patient's blood and removing carbon dioxide, so the individual has much improved exercise tolerance and can function much better. 2) Cells in the transplanted tissue contain healthy copies of the CF gene (from the donor) and so are not affected by the disease in the same way as the patient's own lungs were.

In such a transplant it's not just the CF gene that will be different - the tissue will express may different protein epitopes (because there are many polymorphisms (different forms) of different genes in the population), but the immune response is controlled by immunosuppressive drugs (such as cyclosporin or tacrolimus), so this is not an issue.

Chris

[another_someone]

If an immune response to factor VIII is such a problem, why are not immunosuppresants used in those cases (I accept that you would not want to use them in the first instance, because they increase the likelihood of disease, and have other side effects; but when the immune response becomes serious, are they then used?).

[Negin -(Universe)]

If an immune response to factor VIII is such a problem, why are not immunosuppresants used in those cases (I accept that you would not want to use them in the first instance, because they increase the likelihood of disease, and have other side effects; but when the immune response becomes serious, are they then used?).

i guess, as you said, immunosupressants would be the last option. specially in the case of young children I dont think it would be a good idea to expose them to immunosupressants everytime they have to have an operation or dental work done. their immune system might then become totally insensitive to foreign bodies!!!

[Negin -(Universe)]

quote author=chris link=topic=7563.msg84662#msg84662 date=1178538355]
That's right. Any protein which is different to one that we already find in the body is viewed as hostile and foreign by the immune system, which raises a response against it.

A good example of this is in people with the bleeding disorder haemophilia, which is caused by a lack of blood clotting factor VIII (and more rarely factor IX). They can be treated by injecting the missing blood factor, but because they lack this protein normally, eventually the immune system mounts a response against it in the form of circulating antibodies that bind to it and prevent it from working. This is known as an inhibitor and affects up to 40% of haemophiliacs. The result is that patients need to use much bigger doses of factor VIII to achieve the same effects and in some cases their treatment may even stop working.

In the case of cystic fibrosis, a lung transplant is offered when a patient's own lung function has deteriorated to the extent that they cannot survive. The transplant works for two reasons. 1) The new lungs are healthy and hence better at oxygenating the patient's blood and removing carbon dioxide, so the individual has much improved exercise tolerance and can function much better. 2) Cells in the transplanted tissue contain healthy copies of the CF gene (from the donor) and so are not affected by the disease in the same way as the patient's own lungs were.

In such a transplant it's not just the CF gene that will be different - the tissue will express may different protein epitopes (because there are many polymorphisms (different forms) of different genes in the population), but the immune response is controlled by immunosuppressive drugs (such as cyclosporin or tacrolimus), so this is not an issue.

Chris [quote/]


by the way, chris thank you for confirming that my explanation was right, it shows that I'm actually ready for my A-level Biology exam!

[kdlynn]

ok i think i understand. i just wish they could figure this out quickly and cure the disease. she's only eighteen and she has a permanent iv port thingy and spent her birthday, prom, and graduation in the hospital. so sad

[Karen W.]

What about Heart transplants, How successful are they these days? What about anti-rejection drugs.. infection and all that.. what kind of chances does a person have these days during that procedure assuming they were able to find a compatible heart? Have there been implications to memories or weirdness associated here. I know Chris stated that it is rubbish for the most part , but like others I have heard detailed stories and they may be stories but I would like to know ..

[another_someone]

What about Heart transplants, How successful are they these days? What about anti-rejection drugs.. infection and all that.. what kind of chances does a person have these days during that procedure assuming they were able to find a compatible heart? Have there been implications to memories or weirdness associated here. I know Chris stated that it is rubbish for the most part , but like others I have heard detailed stories and they may be stories but I would like to know ..

Heart transplants seem to be very successful, insofar as you might measure life expectancy (and an improvement in the quality of life for those with a severely failing heart).  They cannot give you a 'normal' life because you will need life long immunosuppresents, and eventually despite the immunosuppresants, they will succumb to rejection - but it could be 20 years down the road, so for someone who is likely to die within 6 months, an additional 20 years of life is significant (and, theoretically, you could then get another heart transplant in 20 years time - only problem is there are not that many hearts around).

The memory issue - well you know the official answer, and you know some of the other anecdotal reports - no-one can tell you who to believe.  The only thing I would add is that even with regard to the reports of cellular memories, they are reported as only being very minor effects, so even if they are true, will be the least of your concerns given the severity of the problem you are trying to solve, and the problems with long term immunosuppresants.

[Karen W.]

Thanks George.