Every organ transplants save thousands of lives, but what happens if your body rejects
the new organ?
Hey guys, Julia here for Dnews
The first successful liver transplant was performed in 1954.
Since then the techniques have improved over the years.
29,000 organ transplants are performed in the United States every year.
But it’s a tricky business.
Matches are rare and rejection can get pretty nasty.
And rejections happens more often than you might think.
While some types of transplants are more successful, like cornea transplants have a 75% success
rate over ten years and five-year organ survival rates for heart, kidney and liver transplants
is about 70 percent.
But on the other hand, according to the National Kidney Foundation, 17% of kidney transplants
fail within three years.
While the survival rate of lung transplants is surprisingly low, like 66% after three
years according to report from the Children’s Hospital of Pittsburgh.
When a person gets a new limb or organ, their body obviously recognizes it as foreign.
and like most foreign things, it tries to get rid of it.
So what happens when someone’s body rejects a transplant?
There are three main kinds of rejection, hyperacute, acute and chronic.
Hyperacute happens almost instantaneously, within minutes or hours, the recipient's body
starts to reject the new organ or limb.
Acute rejection can occur within a few months to a year from transplantation.
Chronic rejection can happen over a few years.
Basically, your body uses its immune system to fight off any foreign invader, whether
that’s a virus or a new liver.
A hugely important part of the immune system is the Major histocompatibility complex (MHC).
The MHC’s main job is to differentiate between your body’s cells and not your body’s
cells.
The MHC is made up of mostly glycoproteins on the walls of your cells.
They act as tags that say THIS IS ME.
When a white blood cell reads that tag, it’s like okay cool, I won't destroy you.
There’s over 20 genes that code for the MHC and over 50 variations PER GENE.
So there’s a lot of combinations.
I mean.
A LOT.
This is why it’s so hard to match a donor to a recipient.
When the MHC recognizes the tags as foreign, it starts a process that triggers destruction
of the weird scary unknown cells.
Your immune system produces T-Cells which go in and target the foreign cells and induces
Apoptosis or programed cell death.
other cells and proteins get involved too, like phagocytes which basically eat up the
dead cells.
Anyways it’s a messy process.
You can tell your body is rejecting an organ in a few ways, swelling or redness, generally
feeling ill and specific kinds of organ failure.
But there are ways to beat rejection.
Most of it involves immunosuppressive drugs, which can include corticosteroids such as
prednisone.
While right after the transplant, the dose of medication is pretty high, but doctors
might ween the dose over the course of a year to a "maintenance phase".
But the thing is, most people have to be on the medication for life, sometimes up to 12
different medications every day.
And because the drugs lower their immune system, they put themselves at risk for infections,
illnesses, and even certain types of cancer.
They have to forever walk a fine line between rejection and infection.
But research is being done to try to remove the need for such drugs.
Some recent research from UCSF holds some promise.
In a study published in American Journal of Transplantation the researchers used a two-tiered
approach to tackle rejection.
First they administered a drug called cyclophosphamide to mice which had transplanted tissues.
The drug effectively killed off most of those T-cells I mentioned earlier.
Then the mice received cell therapy which grew populations of certain cells called TREGs,
and like that name suggests they regulate T cells.
And with more of these cells in place, they hold back the immune system from rejecting
the organ or limb.
According to the study nearly 80% of the mice accepted a transplant without the need for
a lifelong regimen of drugs!
And this technique proved successful in one patient already!
So that could be pretty cool one day.
But it’s clear more research is needed.
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