What is HLA matching?

What is HLA matching?

So typically it's done through blood. So what they do is they'll take there's a number of ways to do it. One is say you take two cells and you sort of look at the proteins on the surface and you try to characterize those and those are the HLAs. And there are essentially six different flavors. It's like A, B and C, and then DR, DP, DQ. So there's six of them they look at, and then if you look at that, that's set in the patient and then you look at that set in the donor, you can see if they match up. That's one way to do it. Another way to do it is by looking at the genes themselves that generate those proteins. So you can do it in a genetic testing as well. That's kind of how more how it's done with oftentimes like with DNA tests where you take a cheek swab and get DNA that way. So we're not getting blood cells that way to look at it. We're getting more DNA to do it. And when we do HLA typing and maybe we look at the blood cells or maybe we look at the DNA. So it just depends on how the typing is done. It is facility by facility, but a lot of times like if you live on the other side of the country, we can just send a kit out to you and then you take it, you take it to a lab, get the blood drawn, and then that gets shipped to us. So it is you don't have to go to the center, be at the center to see if you can donate. To see if you match. It is can be more variably done then.

How closely do patients need to be HLA matched to their donors?

So I think that the consensus is generally that you should be 100% matched. So these 66 different proteins, sets of proteins. If you have the same exact matches at those, then that is great. That's like sort of the ideal. That's for transplantation started out. At this point in time. You can have like probably one of them be mismatched. So 11 are okay and the last one is not. That might be okay in some instances. Nowadays, I think that if you're half matched in many centers, that's all right. So it just depends on the type of transplant, depends on the center you're at, what the match needs to be. It used to be that if you didn't have a perfect match, then there was a big problem. Now, I think it's much, much less of a problem, especially with this idea of having identical transplants.

How does HLA matching affect your risk of graft versus host disease?

It can definitely increase your risk of graft versus host. But it depends on how you do the transplant. So, if we did a haploid identical transplant using the same methods we had 20 years ago, the rate of GvHD would be extraordinarily high. And then the other thing that would happen is that the immune system of the patient would really be primed to destroy the new marrow coming in. So you'd have a lot of rejection. So the way that we do transplants these days where we change how the immune system is suppressed of the patient and we change how we do the suppression of the immune system after the transplant. Now, in some cases there's no access to GvHD rate for a haplo as it is for a fully matched person. So it all depends on how you do the transplant. And in some cases it is no different than doing a matched one. So Hopkins we did a lot of matched and haploid transplants. So if we had a patient who was in their seventies and they had a fully matched sibling or they had a child who was half matched in their thirties, I would always take the child. I would take a half matched younger person over a fully matched older person. So using GvHD rate depending on, like I said, how you do it can be very much minimized for both of those things, but especially for haploid identical transplant.