anti-A1 or rouleaux?

[WMMTSBB]

I had a patient that had an ABO discrepancy. Testing is as follows:

anti-A: 4+, anti-B: 4+, A1 cell: 1+s, B cell: 4+, Screen cells I.S.: all negative, LISS 37: all negative, poly AHG: all negative. Group O donors I.S.: negative, Group A donors: 1+ to 2+. Saline replacement for A1 and group A donors: negative. Microscopically, the A1 and A donors do not really appear as rouleaux. So the question is why do we see apparent rouleaux only with the A cells and not the screening cells?

[Malcolm Needs ★]

Almost certainly because it is anti-A₁, rather than rouleaux, or any other "cold" antibody specificity, such as anti-ALe^b, but, come what may, unless the reactions are positive at STRICTLY 37^oC, it will not be a clinically significant antibody.

[seraph44]

The forward type is an AB patient, your reverse type looks like you have multiple things going on. Because of the negative xm with group O donor red cells and the 1+ reactions with your group A donor red cells, I suspect an anti-A1. However, that 4+ reaction on the B cells cannot be due to the anti-A1 and I highly doubt that it is due to rouleaux; At least from my experience I don't typically see rouleaux this strong and we should have seen it with similar strength against the A1 cells. I agree that you probably have a cold reactive allo antibody going on with the B cells.

In order for you to clear the ABO discrepancy I would do an IS antibody screen and see if you find a patter for a common cold antibody. Hopefully your find something; if you find a Lewis antibody I would find some random group B units and you should statistically land on one that can give you a negative result against your patient plasma to confirm it is not an ABO incompatibility issue. If you find something like an M, you could antigen type a group B unit but that will take 5-6 units before you find one, and then test it again your patient plasma to confirm negative results.

The easier way out is to prove your anti-A1 and then take your reverse cell testing to the AHG phase to rule out ABO incompatibility. Consult with your pathologist of course, since this might be out of your standard operating procedure. 

[Yanxia]

If the reverse reaction with B cell was a typo, I agree with Malcolm, it is an anti-A1or anti-ALe^b. As for the negative saline replacement result, since the neat plasma reaction is weak, it maybe weaken by the test method.