We had an 65 years old male pacient with A2B Rh(D)+ blood type.Never transfused before,antibodies screening negative.We asked our blood bank transfusion guidelines for this pacient in case of need(he was hospitalised for heart surgery).We got the answer that we can give him AB Rh(D)+ regular red cells (the chances he would develop A1 antibodies is 20 percents as far as I know) and only later,if he develops that antibodies we should switch him on B or O.What do you think about this?Is this correct in your transfusion policy?
(Lucky pacient didn't need transfusion of red cells after all,only FFP)
Just to satisfy my curiosity...and learn,of course.
 

Absolutely the advice given to you was correct.

For a start off, as you say yourself, 80% of A₂B individuals do NOT make an anti-A₁, but of those 20% who DO make an anti-A₁, how many will make that anti-A₁ as a result of immunisation as a result of transfusion or pregnancy?  The answer to that, if you read any book concerning blood group serology (and that is NOT a criticism of you - we all started somewhere, including the very best, such as Herr Dr Willy Flegel, and others - and I have HUGE respect for Willy), you will see that a clinically significant anti-A₁ is amazingly rare.

For an anti-A₁ to be clinically significant, it has to react strictly at 37^oC, and that is a VERY rare "animal", and no example of anti-A₁ has EVER been implicated in a case of HDFN, so, PLEASE, do not worry about giving A₁B (or even A₁) blood to an A₂B individual, even if they have an anti-A₁ in their circulation, UNLESS they have an anti-A₁ that is actually active at strictly 37^oC.

Thank you,Malcom,your answer was very useful to me!I have so much to learn from you!

My pleasure.

We have a liver transplant patient AsubB with an anti-a1 (cold).  Our computer allows electronic "XM".  Do you agree with this or recommend a serologic XM?

As long as the anti-A₁ remains "cold reacting" only, and the thermal amplitude does not widen, the clinical significance remains as "not clinically significant", and, personally, I would happily transfuse blood by electronic issue.

Even if the thermal amplitude does widen, unless the anti-A₁ actually reacts at strictly 37^oC, it will remain as "not clinically significant", but I would, nevertheless, perform a serological cross-match - "just as belt and braces".

Thank you!

We have a 19 yr. pregnant female, front type Apos, back type 1+ A1cells and 4+ Bcells. (in gel) No history available.

Tube test with A1 cellls=1+; A2 cells=0; two different O cells=0; and B cells=0.

Anti A1 Lectin = 1+

Antibody screen negative

Results the same with different lot A1 cells. Strength increases with cold incubation.

Crossmatch in IgG at 37 degrees with patient plasma and A1cells is 1+. (in gel)

We are having the patient re-drawn for confirmation, but do I call this weak A subgroup if all results confirm? Clinically significant? Transfuse O cells?

Or could this be pregnancy related?

Edited April 2, 20187 yr by Jennifer Castle

It is important to remember that there is a sort of continuum between the various A types (including A₁ and A₂) in terms of the number of A antigen sites expressed per red cell, and that there is no such thing as an absolute A₁, absolute A₂, absolute A₃ and so on and so forth.  In addition, of course, the lectin Dolichos biflorus is NOT an anti-A₁, but is a lectin that "recognises" the A antigen, the Tn antigen and Cad antigen, as well as the A₁ antigen.  It will not recognise the A antigen if it is diluted correctly, but every now and again, there will be an "overlap" between a "strong A₂", and a stronger than normal Dol. b. reagent.  In addition, there are people who are A_int, or A intermediate, who are somewhere between an A₁ and an A₂.  SUch people usually hail from the south of the African continent, but not always.

As we are looking at ABO, I am not for one minute surprised that the reaction strength increases with cold incubation.

The next thing to remember is that, with gel, it is all but impossible to add the reagents to the reaction chamber so that they remain exactly at 37^oC, which means that IgM antibodies, such as anti-A₁, which it looks like this pregnant lady has in her circulation, will sensitise A₁ red cells prior to true incubation at 37^oC, but will not elute quickly enough to give negative reactions after 37^oC incubation, particularly after centrifugation.

Anti-A₁ is NOT clinically significant, unless it reacts STRICTLY at 37^oC, and this can really only be shown by a pre-warming tube technique, in which case A₂ blood (or other A subtypes, such as A₃, A_x and A_m) can safely be transfused, keeping your precious group O units for group O recipients.  Anti-A1 has NEVER been implicated in clinically significant HDFN.

None of this is pregnancy related.

Thank you!