Jump to content

ABO discrepancy help!


Bb_in_the_rain

Recommended Posts

Patient was historically typed as A postive in Korea. 

Red cells typing 

Anti-A= 4+, anti-B=3 ( same strength with 2 different sources of antisera)

One of the Anti-B includes ES4 clone and one of the Anti-A includes MHO4 clone. 

Tested with 3 more sources of monoclonal and 2 more sources of polyclonal anti-B. (I cannot find the clone numbers on them) 

2 of 3 monoclonal anti-B reacted 2+ and 1 of 3 monoclonal anti-B was negative. 

1 of 2 poly anti-B reacted 2+,  and the other was negative. 

The patient cells were also tested with 2 sources of fresh AB plasma (10 minute incubation, room temperature) to exclude polyagglutination or B(A) ; they were both negative

Autocontrol was also negative (10 minute incubation, room temperature). 

Please let me know what you think about this case. 

Link to comment
Share on other sites

To be honest, I think we need a little more information, such as the underlying pathology of the patient, including whether or not they have recently had a bacterial infection.

In addition, we need to know if an anti-B is still detectable in the reverse grouping.

I can put my hand on my heart and say that I am simply AMAZED that a monoclonal anti-B is still available that contains ES4 as a clone, following the publication of the paper by Garratty G, Arndt P, Co A, Rodberg K, Furmanski M. Fatal hemolytic transfusion reaction resulting from ABO mistyping of a patient with acquired B antigen detectable only by some monoclonal anti-B reagents. Transfusion 1996; 36(4):351-357.

The reason you can't find the clonal numbers for the polyclonal anti-B reagents is almost certainly because they are human-derived, and so are quite literally polyclonal, and nobody would have a clue of the clones involved!

This case sounds (from the distance of the entire Atlantic Ocean, and not seeing the actual results of the tests with my own eyes) very much like a case of an acquired-B (if there is anti-B in the patient's plasma, it would NOT react with the patient's own cells and, indeed, would not react with another individual's red cells who has an acquired-B antigen, caused by the same bacterial strain).

Link to comment
Share on other sites

3 hours ago, Malcolm Needs said:

To be honest, I think we need a little more information, such as the underlying pathology of the patient, including whether or not they have recently had a bacterial infection.

In addition, we need to know if an anti-B is still detectable in the reverse grouping.

I can put my hand on my heart and say that I am simply AMAZED that a monoclonal anti-B is still available that contains ES4 as a clone, following the publication of the paper by Garratty G, Arndt P, Co A, Rodberg K, Furmanski M. Fatal hemolytic transfusion reaction resulting from ABO mistyping of a patient with acquired B antigen detectable only by some monoclonal anti-B reagents. Transfusion 1996; 36(4):351-357.

The reason you can't find the clonal numbers for the polyclonal anti-B reagents is almost certainly because they are human-derived, and so are quite literally polyclonal, and nobody would have a clue of the clones involved!

This case sounds (from the distance of the entire Atlantic Ocean, and not seeing the actual results of the tests with my own eyes) very much like a case of an acquired-B (if there is anti-B in the patient's plasma, it would NOT react with the patient's own cells and, indeed, would not react with another individual's red cells who has an acquired-B antigen, caused by the same bacterial strain).

Opps (again), my apology for incomplete information. The patient is pregnant and no infection was noted. The plasma was non-reactive with A cells and reactive (2+) with B cells. 

Even though the serology initially "smells" to me like an acquired B, the diagnostic is pregnancy with no signs of infection. 

Moreover, only 1 of the 2 known monoclonal anti-B is confirmed to include ES4 clone and the other includes B005 clone, yet both of them were reactive strongly (3+). So I am really puzzle as to whether it is A(B) or simply a subgroup of B. It will be nice to have an example of cells from an individual with acquired-B to test it out, but we do not have these. 

If the reactivity is due to tartrazine in anti-B, I would see a positive reaction with all 7 anti-B that I have tested (as they certain are yellow and I assume they all have tartrazine in them). But that was not the case.....only 5 of 7 anti-B were reactive. 

My question is

As I saw AcqB characterized as a polyagglutination in Issitt and Anstee's textbook (table 42-3), does it mean that I can exclude Acq-B based on the non-reactivity with Fresh AB plasma? 

Would that be a good idea to send it to genomic lab to see if there is any B-transferase present in this patient? 

 

Link to comment
Share on other sites

12 hours ago, Bb_in_the_rain said:

As I saw AcqB characterized as a polyagglutination in Issitt and Anstee's textbook (table 42-3), does it mean that I can exclude Acq-B based on the non-reactivity with Fresh AB plasma? 

Would that be a good idea to send it to genomic lab to see if there is any B-transferase present in this patient? 

An Acquired-B isn't a true type of polyagglutination in the way that is, say, a T or Tn, but is, rather, a deacetylation of the immunodominant N-acetyl-D-galactosamine of the group A antigen, which makes the immunodominant sugar residue so close to the D-galactose of the B antigen, that some anti-B reagents will react with it.

Because this is a "phenotype" type of thing, I don't think genotyping would help, but sending a sample to a good Reference Laboratory (and, as yan xia says, lowering the pH of the anti-B) should help.

Link to comment
Share on other sites

10 hours ago, yan xia said:

It seems like an acquired-B to me. Maybe you can try to lower the pH to 4.5 to see the  lady's cells react with anti-B reagents.

 

6 hours ago, Malcolm Needs said:

An Acquired-B isn't a true type of polyagglutination in the way that is, say, a T or Tn, but is, rather, a deacetylation of the immunodominant N-acetyl-D-galactosamine of the group A antigen, which makes the immunodominant sugar residue so close to the D-galactose of the B antigen, that some anti-B reagents will react with it.

Because this is a "phenotype" type of thing, I don't think genotyping would help, but sending a sample to a good Reference Laboratory (and, as yan xia says, lowering the pH of the anti-B) should help.

Thank you very much for your guidance and advises. I would like to try acidified sera using 1M HCl to repeat typing of this patient's cells. I am wondering what source of anti-B would you acidify? I assume I would acidify the clones that was previously reactive (including the ones with ESO4 clone and polyclonal anti-B)? 

So the purpose of testing with acidified anti-B is to re-acetylate the A(B) into A antigen. Is that correct? So I should expect clones if anti-B that were previously reactive to be negative with the patient's cells after being acidified. 

I think sending it to another Reference is a good option; however, the submitting hospital has decided to give Group A blood and not to further investigate that. So we are left with the tools that we have here in this lab. I hope the acidified anti-B will give me a clue to whether it is A(B) or not. :wacko::unsure:

I will keep you guys updated after I am done with the test. 

With regard to genotyping, if (hypothetically) speaking (and I do not mean to be picky), if the gene that transcribed B transferase is detected, it could mean this is a subgroup of B rather than a A(B)? 

I might be listening to horsehoof and thinking of Zebra. Somehow, I am not convinced that this is an Acquired-B... The diagnostic does not make sense and also one out of 2 polyclonal anti-B is moderately reactive, and both ES4 and B0001 clones were strongly reactive (3+). It is not quite adding up in my mind. I thought I should see somewhat of the difference in reactivity between ES4 and other clones. 

Edited by Bb_in_the_rain
Link to comment
Share on other sites

1 hour ago, Bb_in_the_rain said:

1.  So the purpose of testing with acidified anti-B is to re-acetylate the A(B) into A antigen. Is that correct? So I should expect clones if anti-B that were previously reactive to be negative with the patient's cells after being acidified. 

2.  I will keep you guys updated after I am done with the test. 

3.  With regard to genotyping, if (hypothetically) speaking (and I do not mean to be picky), if the gene that transcribed B transferase is detected, it could mean this is a subgroup of B rather than a A(B)? 

1.  No, not quite.  Acidifying the antisera will not affect the red cell antigens.  It is just that the anti-B reagents will not react with the acquired-B antigen at this pH.

2.  THANK YOU!

3.  I agree, but I think this finding is doubtful, as why would the weak B antigen have not been detected before?

Lastly, ES4 is renowned for reacting with the acquired-B phenotype, but that does not mean that other clones are out there that will also react with the acquired-B antigen, and maybe B0001 is one of these.

You have presented us with a VERY INTERESTING case.

Link to comment
Share on other sites

17 hours ago, yan xia said:

It seems like an acquired-B to me. Maybe you can try to lower the pH to 4.5 to see the  lady's cells react with anti-B reagents.

 

13 hours ago, Malcolm Needs said:

An Acquired-B isn't a true type of polyagglutination in the way that is, say, a T or Tn, but is, rather, a deacetylation of the immunodominant N-acetyl-D-galactosamine of the group A antigen, which makes the immunodominant sugar residue so close to the D-galactose of the B antigen, that some anti-B reagents will react with it.

Because this is a "phenotype" type of thing, I don't think genotyping would help, but sending a sample to a good Reference Laboratory (and, as yan xia says, lowering the pH of the anti-B) should help.

I have tested the patient's cells with 2 sources of acidified anti-B as your guidance. After 5 minute incubation, the patient's cells were non-reactive with one source of anti-B and 1+ with the other source. I used AB donor cells as control and they both remained 4+. I think I can accept that this is an A(B). 

My question is 

Why do we see this in the prenatal patient without signs of infection? I thought acquired B was found in those with cancer and infections? Does it mean that she has an abnormal galactosyl transferase? 

Thank you very much for your guidance and walking me through this case. I should have listened when the experts said it was acq-B!!! Thank you so much again for your guidance!! 

Link to comment
Share on other sites

Geoff Daniels, in his book Human Blood Groups (3rd edition, 2013, Wiley-Blackwell) quotes three cases in the literature where an acquired-B antigen has been detected in apparently healthy individuals, although the first reference he quotes suggests that there have been others.  It could be that, if your patient does turn out to have the acquired-B phenotype, she is another, and that the pregnancy is purely coincidental (although I have my doubts about that being a coincidence).  Anyway, the references Geoff quotes, if you want to read them, are:

Lanset S, Ropartz C.  A second example of acquired B-like antigen in a healthy person.  Vox Sang 1971; 20: 82-84.

Herron R, Young D, Clark M, Smith D S, Giles C M, Poole J, Liew Y W.  A specific antibody for cells with acquired B antigen.  Transfusion 1982; 22: 525-527.

Kline W E, Sullivan C M, Bowman R J, Linden M.  Acquired B antigen and polyagglutination in an apparently healthy blood donor.  Rev Franc Transfus Immuno-Hemat 1982; 25: 119-126.

Link to comment
Share on other sites

  • 2 weeks later...

You were right about "although I have my doubts about that being a coincidence." It was not a coincidence. The Sanger sequencing on this lady indicated that the patient is cisAB.01/O.01. 

In Geoff Daniel's Human Blood Group text book, page 43, described that sera from cis AB people almost always contain weak anti-B. This is a great learning case indeed! 

Have anybody tried testing acidified anti-B with known cisAB cells? I am wondering if acidified anti-B would be non-reactive with cisAB in addition to A(B)? 

 

Edited by Bb_in_the_rain
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Advertisement

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.