Has anyone observed anti-Jka in an eluate of an individual who is Jka negative and received only Jka negative units?

If so, can you offer an explaination?

Thanks!

I have not seen that but I have seen it with Kell. Pt has anti-K, always receives K= rbcs, always a +DAT with anti-K in the eluate (I don't think it's the Matahasi-Ogata phenomenon because there was never another antibody present - that we could detect).

What is the age of the patient?

Patient is 58 years old

I have not seen that but I have seen it with Kell. Pt has anti-K, always receives K= rbcs, always a +DAT with anti-K in the eluate (I don't think it's the Matahasi-Ogata phenomenon because there was never another antibody present - that we could detect).

I've seen this too in a patient at QEQM Hospital in Margate, Kent. No K+ blood given in decades, patient K-, clear anti-K in the eluate, no other antibodies.

I think it is just another mimicking antibody missyg. I just wish that the blank, blank things would read the books and stop being horrible to us!!!!!!!!!!

I think some bacterial infections cause these mimicking red cell antibodies

And u are positive they did not get blood elsewhere. I had a mystery but eventually solved when discovered lady got a unit 3000 miles away when taken to ER for car accident. She was unconscious and did not know she got blood. Finally instead of asking if she got blood I asked if she was treated in any hospital. Oh yeah. She said. For car accident. I called them. Mystery solved. 4 units.

Reaching here. Did any of the Jka Neg donors have anti-Jka? I realize that most of the plasma is removed from the RBCs these days, but stranger things have happened.

We see this a few times a year, mostly with anti K. I agree with Malcolm that it are mimicking antibodies. We only see it when we make an acid elute (Immucor), not when we make an ether eluate.

Peter

As John C Staley has pointed out in the past (and he is absolutely correct), I have a habit of looking for zebras, rather than horses, when I hear hoofbeats!

That having been said, I have just read an interesting paperWebster ES, Storry JR, Olsson ML. Characterization of Jk(a+weak): a new blood group phenotype associated with an altered JK*01 allele. Trasnfusion 2011; 51: 380-392.

This involves a rare (allele frequency 0.042) 130G>C point mutation, resulting in a Glu44Lys substitution in the mature protein, leading to a gross weakening of the Jk(a) antigen. They say in the paper that, if this antigen is missed, it could lead to the formation of anti-Jka and a possible delayed haemolytic transfusion reaction.

There is the very slight possibility, therefore, that one of the donors who was typed as Jk(a-) could have this mutation and actually be Jk(a+weak).

I will now get back to the normal world!!!!!!!!!!

:devilish::devilish:

I also have seen anti-K in a K negative patient. The elution was perfect, clear cut. My guy was 80+ years old and had never ever even been in the hospital, much less been transfused. Definitely mimicking.

What type of AHG reagent are you using? I have recently learned that sometimes anti-Jk^a will not be detected unless the AHG reagent includes complement. Using monospecific anti-IgG can miss some anti-Jk^as.

Ah, but the point is Catherine that missyg is detecting the anti-Jka in the eluate, but that the patient appears not to have been exposed to the Jk(a) antigen.

Thank you all for the suggestions!!! We are trying some other techniques and contemplating having the patient genotyped. As far as we are told the patient was not transfused anywhere else. The patient does not have bacterial infections and is awaiting liver transplant. I will update you all as soon as we have results!

I just came across a letter to the editor in Transfusion about “naturally occurring” anti-Jk^a. It is in Transfusion, Volume 45, Issue 6, pages 1043–1044, June 2005

It involves a case of “naturally occurring” anti-Jk^a in a 7-month-old boy with orchitis, epididymitis, and an Escherichia coli urinary tract infection.

An antibody detection test was positive and anti-Jk^a was identified by gel test using a low-ionic-strength saline. Repeat antibody detection tests were the same during the patient’s 8-day hospitalization. 6 months later the antibody detection test was negative.