Adventures of a Kidney Donor

November 14, 2010

Matching Donors and Recipients

I thought I should write a little about the testing process that is now going on with the blood drawn from the potential kidney recipient and me last week. I am anxious about the results and I imagine the recipient is really anxious!

Living Donors Online explains the matching process:

 

 Blood Type …As a general rule, you must have a blood type compatible with the recipient or you will not be able to donate. Here is who can donate to whom:

Type A can donate to types A and AB.

Type B can donate to types B and AB.

Type AB can donate to type AB.

Type O can donate to types A, B, AB, and O.

Tissue Type. A second test of compatibility looks at the match of human leukocyte antigens (HLA). There are many different kinds of antigens, but there are three categories assessed for kidney donation, designated HLA-A, HLA-B, and HLA-DR. You inherit one set of these three antigens from each parent giving you a total of six HLAs.

Your antigens are determined by drawing blood and testing it. A similar test is run for the recipient, and the antigens are compared. The closer the match the better because the recipient is less likely to reject the donated organ. You might hear of a “six-of-six” match (all donor and recipient antigens match) or a “half match” (three of the six antigens are the same) or a “zero match” (none of the antigens matches).

There was a time when this type of tissue compatibility was important. However, the development of more effective anti-rejection drugs has reduced the importance of the HLA match. In fact, some transplant teams ignore tissue typing. Therefore, even if your degree of matching with the donor is relatively low, you may still be considered for donation.

Crossmatching. The third blood test is an important one. Crossmatching is a further testing of antigen compatibility. In this test, white blood cells from you are mixed with blood from the recipient. If the white blood cells are attacked and die, then the crossmatch is “positive,” which is a negative as far as your ability to donate. It means the recipient is “sensitized” to you—the recipient has antibodies to some of your antigens—so the recipient’s immune system would turn on the donated organ and destroy it. If the crossmatch is “negative,” you are compatible with the recipient.

Friends Sarah and Lisa have written a great blog GottaGetaKidney on their kidney donation experiences and Sarah kindly commented on my blog. Lisa has a good explanation of the matching process:

In one of my earlier posts, I wrote about the three things the team uses to match a kidney to a recipient.  The first is blood type, A, B, AB, or O.  Next is Human Leukocyte Antigens (HLA).  There are six of these and you get 3 from each parent.  Last are the donor specific antibodies, as measured by a PRA (Panel Reactive Antibody) score.  I am lucky in that my blood type is AB, the universal acceptor, so I can accept any blood type.  I am unlucky in that I had a high PRA score with a lot of antibodies because of the pregnancy and all the blood products I received after I delivered.  I was a one match/five HLA mismatch with Sarah.  Not ideal, however; immunosuppressant medications are so good these days that the difference in the life of a kidney between a 5 match/1 mismatch and a 0 match/6 mismatch is only a matter of months.  If you are lucky enough to find a perfect 6/6 match, the body reacts like the kidney is its own and that is the best situation.

Resources:

 

Go to List of Resources on Kidney Donation

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2 Comments »

  1. Thanks Anne. I think about you frequently. My best wishes to you both. Joan

    Comment by Joan Smith — November 15, 2010 @ 6:19 am |Reply

  2. Theresa and I were a 1/6 HLA match and I’m still pluggin’ along! I can’t tell you how awesome I think you are, Anne, I’m so blessed to have met someone like you and can’t wait for me , you, Jackie & Theresa to get together.

    Comment by Kiersten Hedke — November 15, 2010 @ 7:57 am |Reply


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