What's a high frequency antigen that might be weakened on expired reagent cells, reacts in Ortho MTS gel testing (about 1+), including when 3% cells are converted to 0.8% to run in gel but not in PEG? It does not react in MTS gel on 2 expired 3% reagent cells converted and run in gel but did react with 3 in-date cells converted to 0.8%. It does not react using 30-minute PEG with any cells in a 16-cell panel.  DAT is neg.  No recent transfusions; 51 y.o. fe with a lacerated spleen from being thrown from a white-water raft onto a rock. Hgb staying stable enough. O pos. "Race: Other White" and she is from Arizona. I would think it was antibody to the gel diluent in prediluted reagent cells but then the converted cells using diluent 2 should not react.  I am tempted to trust the PEG results but thought I would ask.

Maybe it is a cold but the diluent 2 was colder for the first run but had warmed up by the second run of 2 additional cells?

Edited July 11, 20241 yr by Mabel Adams

Could be an antigen within the Knops Blood Group System.  They are notorious for "going off" on older red cells, but the antibodies are not renowned for being clinically significant.

Because Knops antibodies usually behave as HTLA-like, I would have expected it to react in PEG as well as gel, but the antibodies do whatever they want!

18 hours ago, Mabel Adams said:

Because Knops antibodies usually behave as HTLA-like, I would have expected it to react in PEG as well as gel, but the antibodies do whatever they want!

True, but I was talking about the antigens on stored red cells, rather than the antibodies.

I haven't seen a rebuttal but the FY system is reported to be a problem with storage. It was reported by :

Williams D, Johnson CL, Marsh WL. Duffy antigen changes on red blood cells stored at low temperature. Transfusion. 1981 May-Jun;21(3):357-9. doi: 10.1046/j.1537-2995.1981.21381201813.x. PMID: 7233520.

You are quite right Jason.  I also remember a similar paper, written by Jill Storry, entitled "Long term preservation of red cell antibody identification panels in low ionic strength solution."  This was published in Medical Laboratory Sciences 1987; 44 (4): 350-355, but was based on the winning Margaret Kenwright award presentation at the Annual Scientific Meeting of the British Blood Transfusion Society, London, UK on 4th September 1986.  This was when Jill was a Senior Medical Laboratory Scientific Officer at the South Western Regional Transfusion Centre of the National Blood Transfusion Service in Southmead Road, Bristol.  She has done rather well for herself since then, now being a Professor at Lund University.  Unfortunately, I don't have a DOI for this paper.
 

At the time, I was working at Mayday Hospital in Croydon, London, and wrote to her to clear up a couple of queries I had.  In early January 1988 she wrote back to me and, in this reply, she stated,

"Can I also draw your attention to the fact that the original trial (her original trial) was done using frozen re-constituted red cells.  It has subsequently been pointed out to me that when using fresh cells for screening purposes there is significant loss of Fy(a) and Fy(b) antigens over a two week period.  This phenomenon has been well documented (see below) and is due to the release of proteases upon leucocyte aminoglycoside interaction.  Gentamicin is of course, an aminoglycoside antibiotic.  We have overcome this problem completely by leucocyte depletion using a Sepacell 500 filter,  and I hope to submit a short communication to the IMLS journal describing the results of this modification."  I haven't got a reference for this.

The paper to which Jill was referring to in her letter was:

Malyska H, Kleeman JE, Masouredis SP, Victoria EJ.  Effects on Blood Group Antigens from Storage at Low Ionic Strength in the Presence of Neomycin.  Vox Sanguinis 1983; 44 (6): 375-384.  DOI: 10.1111/j.1423-0410.1983.tb03660.x

All that having been said, I would be surprised if all screening cells and antibody identification cells were not now leukodepleted.  In addition, of course, apart from certain areas of Asia, neither the Fy(a), nor the Fy(b) antigens can be regarded as high prevalence antigens, and those antigens within the Duffy Blood Group System that can be regarded as high prevalence (Fy3, Fy5 and Fy6) are vey different to both Fy(a) and Fy(b), and so it is doubtful that these would weaken substantially upon storage.

4 hours ago, jtemple said:

I haven't seen a rebuttal but the FY system is reported to be a problem with storage. It was reported by :

Williams D, Johnson CL, Marsh WL. Duffy antigen changes on red blood cells stored at low temperature. Transfusion. 1981 May-Jun;21(3):357-9. doi: 10.1046/j.1537-2995.1981.21381201813.x. PMID: 7233520.

 

We had to purchase a set of screening cells from a different vendor for DTT treating cells for Darzalex patients because when we validated it, the Duffy antigen we were testing didn't survive the process consistently.  It was fine on Alba cells but not on Immucor cells.