I just wanted to check and be sure I didn't miss something with this case...

We have an adult male patient who was type B positive in the past. He went in March to another institution and received a double cord stem cell transplant. The institution that performed the transplant assured us that the donors were O positive and B negative (and sent records stating this). We got a sample from him this week that front types as A positive and reverses as AB. When we requested results from the transplanting institution, we saw that they typed him in May as AB positive front and B reverse with no explanation or investigation in the records they sent.

To me, it looks like this patient is in the process of converting from a B to an A. Given that his donors were O and B, that seems very unlikely. My conclusion is that one of the donors was mistyped.

Have I missed a possibility here?

From what you have described, your conclusions seem to be likely that a donor was mistyped. Can you ask for the lab to re-type the donors with fresh samples, or It could be that they misinformed you and meant to say that the donors were O and A ?

Would your consultant need to clarify this in case a mistake had been made...but then I suppose if the HLA types were not matched the transplant would have failed.

Any possiblility of HLA recombination.

From what you have described, your conclusions seem to be likely that a donor was mistyped. Can you ask for the lab to re-type the donors with fresh samples, or It could be that they misinformed you and meant to say that the donors were O and A ?

Would your consultant need to clarify this in case a mistake had been made...but then I suppose if the HLA types were not matched the transplant would have failed.

I agree with you Rashmi, that this seems to be the most likely answer, but given that they were cord stem cells, going back to the donor could be more difficult than normal (although some of the donor cells should have been kept).

When using cord stem cells, however, the HLA match can be less "exact" than when peripheral stem cells are used, because the humoral immune line is still niaive (I can't spell it, but I hope you know what I mean!).

:D

We have obtained a second sample and he is still typing as an A without any ABO antibodies demonstrating. My pathologist has decided that she doesn't want to pursue the matter with the transplanting institution, so I guess we are at an impasse. Thanks for all the comments!

What blood group are you going to give if the patient requires a red cell transfusion?

i think they should give o

What blood group are you going to give if the patient requires a red cell transfusion?

At this point, I would be comfortable giving type A blood. The A front type is 4+ from both samples and the back type demonstrates no anti-A or anti-B. I would guess that this patient will not develop anti-B, given that he is genetically B and probably expresses that on other tissues. The only problem we have is the discrepancy between what we are seeing in the patient testing and what we have been told by the transplanting facility. If they had said he got type A stem cells, there would not be an issue once his type converted.

Edited December 9, 200915 yr by adiescast

At this point, I would be comfortable giving type A blood. The A front type is 4+ from both samples and the back type demonstrates no anti-A or anti-B. I would guess that this patient will not develop anti-B, given that he is genetically B and probably expresses that on other tissues. The only problem we have is the discrepancy between what we are seeing in the patient testing and what we have been told by the transplanting facility. If they had said he got type A stem cells, there would not be an issue once his type converted.

Thanks.

To be honest, that's what I thought myself.

:)