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David Saikin

An Enigma (for me)

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Have only done preliminary studies on this but would  like any/all opinions.

Routine ABORh:  front types as group A, Rh(o)D Negative.  Reverse group w A1 Cells is 2+/B cells:  4+.  Testing is in gel.

Had the tech run the pt plasma in buffered gel vs A1, A2, S1, S2, S3 and auto ct.  15 min @ rt.  Only the A1 cell reacted 2+.  Yes

it is the same A1 cell.  Pt types 4+ with A1 lectin (controls as anticipated).  I do not have a different lot commercial A1 cells.  Will find some

donor A1s tomorrow.  Gel antibody screen is negative with IgG card.

Do not know the diagnosis.  Open to any/all comments and opinions.

Thanks in advance

 

Edited by David Saikin
left out IgG screen result

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The reagent A1 cells we used is a combination of three donor cells which produced by the factory.If the reaction with A1 cells is due to low antigens, maybe we can see mixed field reaction.

I totally agree with your choice of choosing another A1 cells to do the test.

 

Edited by yan xia

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By anti-A1 lectin, I presume you mean Dolichos biflorus (Horse gram)?  Whilst I am not for one minute saying that this is the answer, but it has to be remembered that Dol b is by no means specific for the A1 antigen.  Not only will it also react with Tn+ red cells and Cad+ red cells, but, unless the lectin is diluted correctly, it will react with the A antigen, rather than just the A1 antigen.  In addition, of course, the number of antigen sites varies widely from one individual to another.  In an A1 adult, the number of sites can vary from about 810, 000 to 1, 170, 000.  If your A1 reverse red cell is derived from an individual towards the higher end of this range, and your Dol b is diluted close to the tipping point where it will react with some (but not all) A2 red cells, this may explain your enigmatic situation (it also may not, of course!).  I agree entirely with yan xia that performing the test with another sample of A1 red cells, but I would suggest that testing with a range of A1 samples (say four) would be even better.

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37 minutes ago, exlimey said:

Passive anti-A from a transfusion ? Possibly from a platelet product ?

I may be wrong, but would not such anti-A be adsorbed onto the patient's own red cells, and, considering that ABO antigens are histo-antigens, onto the patient's tissue cells?

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9 minutes ago, Malcolm Needs said:

I may be wrong, but would not such anti-A be adsorbed onto the patient's own red cells, and, considering that ABO antigens are histo-antigens, onto the patient's tissue cells?

Very true and quite possible, especially neutralization by serum antigens. One might even see a positive DAT if the patient's cells sucked-up passive anti-A. On the other hand, a large enough dose of out-of-group platelets might leave some isogglutinins available to mess up the ABO results. Just throwing out ideas.

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I too would go for an antibody outside of the ABO system, active at RT that was present on the original A1 cell.  If this A1 cell is from a single donor, that makes it even more likely.  As Yan Xia said above, if it's a pool, then you might well see a mixed field.  So I would test against (as Malcolm says) at least 4 other A1 cells; and I would test the original A1 cell also at 37°C to see if you are looking at something you need worry about or not

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I ran 3 more A1 cells, one reacted 2+ in buffered gel.  Set up a room temp id.  All cells negative.  I think I am just going to go with an anomalous reverse grouping.  But I am open to any other suggestions.  Patient is not a transfusion candidate.

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14 hours ago, Malcolm Needs said:

I have heard of anti-ALeb, but not of anti-ALea.  I would have thought that, if it was a case of anti-ALeb, it would have reacted with more examples.

Sorry, it was my mistake. I am very sorry.

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