Question about PRA

[Laurie]

I talked to my transplant coordiantor today and asked her what my PRA is. She said for Class 1 it is 0% and for class 2 it is 69%. 
Does anybody know what the difference in the 2 classes are.  I asked her and she said class 1 is AB and class 2 is DR. What the hell does that mean?
 I knew I wasn't going to get the answer out of her, so I thought I would ask here instead.

[kelliOR]

Hi Laurie,

I can surely appreciate your confusion.  This topic took me a long time to wrap my brain around, too!

Here's how I understand it:

You inherit one set of three antigens from EACH parent, known as HLA ( Human Leukocyte Antigens )
So, you have  2 HLA-A,  2 HLA-B, and 2 HLA-DR (remember you get an A,B, and DR from each parent)

Keep in mind that HLA's are proteins located on surface of WBC's and other tissues in the body.

Now, each of the HLA classes has OTHER specific proteins within them. 
Stay with me.....HLA-A has up to 59 different proteins  ( you could have HLA-A1, or HLA-A4, or HLA-A44, etc.)
                      HLA-B has up to 118 different proteins
                      HLA-DR up to 124 different proteins

Now about PRA ( Panel Reactive Antibody )

PRA is determined by testing your serum to a panel of 60 different types of HLA. (no idea which ones)
      If your serum reacts with none, then your PRA is 0%   
      If your serum reacts with 30 out of the 60, then your PRA is 50%  (1/2 of the 60)


HOPE YOU'RE STILL WITH ME........

 Looks like Class I measures HLA-A, and HLA-B.    Class II- HLA-DR

So................If I am right in my understanding, Laurie, your HLA-A and HLA-B had 0% reaction and your HLA-DR had close to a 70% reaction.

NOW...............I'm not an immunologist, but this is how I understand this complicated matter.   


Hope this helps some,    Cheers,  Kelli

[okarol]

  You lost me at antigen     

  Good job Kelli - I wish I could grasp all that! 

[kidney4traci]

Thanks Kelli that was the best way I have ever had someone to explain that to me.  Makes me want to call my transplant clinic!!

[Laurie]

  for the explanation Kelli. I understand it alot better now then I did before.

[KT0930]

Wow, I had no idea there were so many different types. Thanks Laurie for asking and Kelly for explaining!!

[paris]

Kelli, that is exactly how my transplant co-ordinator at the second center I am listed at explained it.  The first didn't even try.  That is why it can be so hard to match with a high PRA.  I have had 5 potential living donors tested and numerous cadaver---no close match.  It is like playing the slots and hoping to get all 7's!  The possible combinations are endless.  But, I live with hope and maybe someday I will get lucky!

[Jill D.]

Good job, KelliOR! My doc at Mayo explained it to me in a similar way, plus he drew pictures. It made perfect sense to my husband and I as Dr. Gloor explained it, but I knew I could NEVER explain it to someone else! At the time that I was doing plasmapheresis in preparation for my transplant, I even knew which specific proteins we were going after that were reacting with my sister's tissue.

[Wattle]

WOW Kelli that is a great explanation.

My PRA is 0% which is great but my HLA matching is not so great. Apparently I have inherited two very rare groups of antigens from my parents. I have the lowest possibility of matching someone out of the pool of organs that become available on the cadaver list.