Wednesday, March 29, 2006

Is Gene Therapy the Way to Go?

Today my wife and I found out that our HLA is only a 50% match with our son. For those of you who are unaware of what HLA is, I will explain. HLA cells are located in all of you organs and tissue in your body. They let your body know what belongs to you and what is foreign (like a virus). There are many locations where HLA reside but there are only really 6 that are extremely important in making sure that your immune system identifies what is yours and what is not. The chances of you having the exact same combination of HLA as someone else in the world at those spots is extremely slim.

That said, when two people produce a baby they supply the child with half of their HLA typing. Just as you are responsible for giving half of the rest of your genes to your child, you and your spouse do the same for HLA. That means Parker got half of his HLA from me and half from his mother. So at the very least, he would be a 50% match with us. The chances of him being any more of a match than that would require there being some strange similarities in my wife and my genetic makeup if you know what I mean (kissing cousins ... hint hint).

Now, why is HLA important? Well, if Parker is getting stem cells from us that would mean that we would not be identical matches. The only way he would have an identical match would for him to have a sibling that got the same HLA from us. When a stem cell transplant is done with parents it is usually the same situation that we are in (3 out of 6) and is called a Haploidentical Stem Cell Transplant. Sick Kids in Toronto has been successful with this type of treatment; however, it has been unsuccessful more often than not. That said, many of the children were far worse off than Parker, as they had already caught several infections. This presentation by the FDA explains the different treatments that have been done for patients with SCID-ADA and how successful they have been.

The first gene therapy trial ever done was with ADA. The reason being is that SCID-ADA is caused by a single gene, it is easy to regulate as it is always turned on in our bodies, and finally the ADA gene only needs to work at a 10% level to be very successful. The main centers that perform gene therapy are Italy, UK, France, U.S., and Japan. Gene therapy has come a long way since its first use in 1991. The protocol has changes several times.

Currently, Italy has been the most successful with gene therapy. They were the first center to attempt gene therapy and have currently done seven human clinical trials in the past five years with their newest protocol. All of which have been successful to some degree. We have currently been told that the center in Italy would accept Parker in their clinical trials. In the following paragraph I will explain the current protocol for gene therapy as performed by the center in Italy.

The procedure begins by removing stem cells from the patient. These cells are then placed in a culture and infected with a retrovirus that has been encoded with ADA. The patient is conditioned with a medication called busulfan (a mild form of chemotherapy: non-myeloablative conditioning) at a relatively low dose to make space in the bone marrow for the growth of new working stem cells. Once the patient is conditioned, the retovirus with the improved stems cells are reinfused into the blood stream. The retrovirus binds to the cell and allows the RNA to create a small piece of corrected DNA that gets inserted into the patients own DNA. When this occurs we have cells in the body that have a working ADA gene in them. Check out this site for a more illustrated version of what happens at the cellular level. Check other then viruses as vectors and work from their.

Many of you may have read or heard about the deaths in France that occured due to children who obtained leukemia as a result of gene therapy. The reason was that the DNA binded to the incorrect spot in the DNA. The trial consisted of 18 patients. Of those, three contracted leukemia, one of those died. As a result, the gene therapy for SCID patients was discontinued in the United States.

It is to be noted that the trials in France did not deal with SCID-ADA but X-Linked SCID. As a result, the ban on SCID-ADA gene therapy has been lifted in the United States as it follows the same successful protocol developed in Milan, Italy.

10 comments:

coolauntiekatie said...

Hiya Parker!

Or should I say Bonjourno!???? Could it be that you're going to be a world traveller at the ripe old age of two and half months??? Anyway, it's too bad that Mommy and Daddy's HLA wasn't a better match..........but I suppose now you can go on your very first adventure!! Hope this news didn't affect your eating! You've been doing so well, and we're very proud of you!

Love ya lots and lots!
Auntie Kate xo

Stacia said...

Parker darling,
You are such a strong STRONG baby!!! Whatever lies in the upcoming months...YOU CAN DO IT!!! :) If anyone ever tells you can't or gives you not so uplifting odds...YOU do everything you can to PROVE THEM WRONG...Trust me, I know and that's what I did!!! You give your mommy and daddy lot's of smiles today...and maybe if you could...give your mommy a VERY SPECIAL HUG from me ok!

Lots of love (and hugs),
Stacyxoxo

Natalie said...

Parker Poo,

I hope that you and your Mommy and Daddy are doing well today dealing with all of this news. Are you going to be traveling soon? If so I know that you will be such a trooper!! You are SUCH a strong, amazing little Monkey and if you decide to travel to Italy they will be so lucky to be able to see your beautiful little face in person! Tell your Mommy to call me tonight so she can fill me in in person! Keep eating, smiling, and getting stronger Parker Poo becasue we all love you SOOOOO MUCH!!!

Love,
Auntie Natalie & Uncle David xoxox

Natalie said...

Hello Parker!!!

Thanks for the pictures Parker Poo! I am so excited to see your little face this morning! You are a little pumpkin!

Have a great day..eat lots and lots baby face!

Love,
Auntie Natalie xoxo

Uncle Michael said...

Well Parker, the Leafs Hockey pool is finished and it's up to me to let you know you still owe me $10.00. Now, I understand that because of your condition you may not have made the best choice in picking the Leafs. But I'm afraid you can't use that as an excuse. So, I'm willing to wait until you're healthy to discuss this further but....until that time, I might have to take "Yarney" as collateral.
Either way, we all love you very much and can't wait for you to get better.
Keep strong. The Leafs may have given up, but I know you're never going to!
Lots of Love
Uncle Michael

nonna said...

Morning Parker,

How was your sleep last night, I hope you got lots of zzzz's, cause that's when you do most of you growing. Your Mommy and Daddy said that your lungs are looking much better, was there ever any doubt about that? I always knew you were a "SUPERBOY" Way to go Big Guy!
Nonno says hello to his handsome boy.
Have a great day.

love you tons.

Nonna and Nonno

Elizabeth said...

Hey little guy,

I am so happy to be able to see your adorable smiling face every day...keep on smiling, you strong boy - no matter what life throws at you! Your smiles, I am sure, make mommy and daddy very happy through all of this. To Parker's Mom and Dad - I am always here for you! A phone call away, and soon, a few houses. Remember that!

Can't wait till your next pictures, Parker!

Love Elizabeth
*hugs*

Natalie said...

Thursday, March 30, 2006.
A beautiful spring day. The buds on some of the city trees are just about to burst into an array of colour. This is my first message Parker, but as you'll eventually learn, I'm not the computer guru that your dad is, but I will touch base once in a while. P.S. In the news today - some crazy guy got off for bad driving after he drove into a house. He said that Shania Twain made him do it. Shania Twain is a hot Canadian country singer. I've got to go. Take care and stay strong.
love,
david

Kyle said...

Wad up Parker.

I have to say you are such a handsome boy!! Quite adorable wrapped in your blankets. It is so nice to see so many pictures of you. And this whole BLOG thing is such a great idea! We log on every morning before we start our work day to read up on how you are doing!! And I'm so glad to hear that you have had some really good days as of late! Keep up the good work and stay strong. You are a true champion. We are extremely proud of you Parker. And please say hello to your parents for us! Thanks... talk soon.

Love, Kyle & Josephine :)

Natalie said...

P.S. Parker Poo...Sometimes your Uncle David will post a message to you under my name. You will be able to tell that it is your Uncle David writing because he will probably fill you in on a story from the news that day! He just wants to keep you posted on all of the current events! We love you Parksy Posey!

Love,
Auntie Natalie xoxoxo