Teen Takes On Donor's Immune System 231
Leibel writes "The Australian ABC News is reporting that a 15-year-old Australian liver transplant patient has defied modern medicine by taking on her donor's immune system. Demi-Lee Brennan had a liver transplant. Nine months later, doctors at Sydney's Westmead Children's Hospital were amazed to find the teenager's blood group had changed to the donor's blood type. They were even more surprised when they found the girl's immune system had almost totally been replaced by that of the donor, meaning she no longer had to take anti-rejection drugs. 'Dr. Michael Stormon says his team is now trying to identify how the phenomenon happened and whether it can be replicated. "That's probably easier said than done... I think it's a long shot," he said. "I think it's a unique system of events whereby this happened. "We postulate there's a number of different issues - the type of liver failure that she had, some of the drugs that we use early on to suppress the immune system and also that she suffered an infection with a virus called CMV, or cytomegalovirus, which can also suppress the immune system."'"
Warring immune systems? (Score:5, Informative)
Actually, if memory serves, NPR had a short bit on a treatment for negating the need for anti-rejection drugs in kidney transplants--they not only transplanted the kidney, but also bone marrow from the donor, and 5 patients out of 6 were able to go off the anti-rejection drugs.
Article: Bone Marrow + organ = no rejection (Score:5, Informative)
Graft Versus Host Disease (Score:5, Informative)
Though given a choice, I'd take the GVHD risk, lose the immunosuppressants, and never worry that my liver graft would fail. All in all she's a hella lucky kid.
Re:Warring immune systems? (Score:5, Informative)
Of course the parents genotype is no absolute guarantee, as it is always "momma's baby, daddy's maybe" but it sounds like they have this pretty well nailed down. She really did develop chimerism.
Re:Self-rejection? (Score:5, Informative)
Re:2 questions (Score:3, Informative)
Re:2 questions (Score:4, Informative)
True to a certain extent. AB could probably handle O, but AB couldn't handle A or B (just the same as A couldn't handle B or vice versa). Having the A markers yourself, as an AB, doesn't neutralise the problems with the B vs A clashwith your B markers and their A markers).
Certainly, when reciving blood, if she was AB positive, she can be a universal recipient. But that would be for an emergency blood transfusion. In an organ transplant situation it would be too risky.
Just as a side note. The problems with different blood types in blood transfusions is less to do with rejection by the immune system and more to do with the blood cells co-aggulating. With a transplant the problem is more to do with rejection by the immune system.
Re:2 questions (Score:5, Informative)
A better article [yourguide.com.au] on this case described her original blood group to be Type O negative(-) with her new blood group being Type O positive(+).
In this special instance, there would be no reaction. Simply stated, anti-bodies can only be generated for antigens. Thus, you cannot have a humeral immune response based upon a lack of an antigen. This, incidentally, is the same reason why a type AB positive(+) person can receive blood transfusions from any blood group.
This is a good point. I can only guess that because the recipient's blood type was rare (approximately 9% of the population in Australia, according to wikipedia) and that the donors blood type was close (and perhaps their major histocompatibility was good too), other factors like urgency might have taken precedence over the ideal hope of a "perfect match."
-Grym
Re:2 questions (Score:2, Informative)
A person with group O can receive blood only from another group O person (but can donate to almost everyone else). RhD negative people who don't have anti-RhD antibodies can receive one transfusion of RhD positive blood then become sensitised to the RhD antigen.
On the flipside, RhD positive people don't react to RhD negative blood.
It's important to realise that the ABO and RhD+/- systems are only the most important parts of the system - there are 29 blood group systems and over 600 known antigens relating to blood type.
Re:The implications are much more profound than th (Score:3, Informative)
We effectively already do this. They're called bone marrow transplants [wikipedia.org], and it's been used to treat a number of blood-based or auto-immune diseases for years.
The risk of this procedure aside, one problem is that bone marrow transplants aren't perfect. Take leukemia or sickle cell anemia for instance. Unless every single hemopoietic stem cell is eradicated (unlikely), there is a risk that the original cell populations will reproduce and the disease will eventually come back.
Umm... no.
Tay-Sachs disease [wikipedia.org] is a lysosomal storage disease [wikipedia.org] which becomes most problematic in the nerve cells of the brain. For obvious reasons, unlike a bone marrow transplant, you can't remove/replace all of the nerve cells of the brain without killing the patient.
Creutzfeldt-Jakob disease [wikipedia.org] is, to put it simply, mediated by a prion (a malfolded protein that induces normally folded proteins to also misfold) which can be either genetic in origin or acquired. Even in the case of genetic CJD, the protein would is expressed in every cell of the body, so a bone marrow transplant would not address the problem. Furthermore, even in the best case scenario where you could replace the entire defective genome without killing the patient, because the defective prion is self-replicating in nature, unless you ALSO replaced every protein in their body too (which, if you could do that, you effectively just be making a whole new body for the person--a cure for all diseases) you'd be in the unique situation of having treated the genetic form of CJD, only to be effectively left with the acquired (and still deadly) form.
Yeah sure. If you're willing to inflict one of the most invasive, riskiest, and painful procedures in medicine upon the entire world's population just for immunity to one disease, I guess you could [/sarcasm].
-Grym
Re:2 questions (Score:5, Informative)
my blood type is O+, the recipient is A+.