Transfusion dependent patients and RBC lifespan

[Auntie-D]

I have a bit of a thought process going on...

 

In our laboratory we issue fresh cells (<14d old) for transfusion dependent patients with the aim of increasing the viability of the red cells between appointments, reducing the number of transfusions and thus donor exposures (and also time ion hospital for the patients).

 

Now we have a patient who has Beta Thal and is transfusion dependent. The patient has anti-Kp(a) - considered clinically insignificant and we crossmatch empirically. We now have the situation that the titre has fallen to a level too low to detect so crossmatching empirically would yield 'compatible' results for incompatible units.

 

No normally an issue - we would transfuse to relieve the symptoms of anaemia and if the cells become sensitised and are cleared early by the spleen, so what...?

 

But what if you have a transfusion dependent patient that you don't want to risk this with?

 

I have tried to order antigen negative units but our donor/reference centre will not issue antigen negative units unless the patient has multiple antibodies. When I phoned to query this, starting the conversation with 'I know we wouldn't normally bother but...' their response was that the couldn't help. When I tried to explain my reasoning I was met with 'but the antibodies are gone now so you can give antigen positive units without a problem'. *Insert agog smiley face at this point*

 

So basically I have got nowhere. In the end units were crossmatched and were issued as compatible - although there is a chance they may not be. We issued them on the basis that with population that have only 2% that are positive for the antigen the chances are the units will be Kp(a) negative anyway.

 

I am just extremely uncomfortable about playing Russian Roulette in transfusion.

 

I know the worst that is going to happen is that the patient will clear the red cells earlier than they normally might and need a new appointment sooner but surely this isn't a good service to offer a transfusion dependent patient?

 

Am I being totally unreasonable?

[galvania]

Do you not have the possibility of testing yourselves?

[Auntie-D]

Do you not have the possibility of testing yourselves?

 

You mean phenotyping the units? We only have basic phenotyping cards/reagents

[Malcolm Needs ☆]

Am I being totally unreasonable?

 

Yes, in a word.

 

To quote Daniels G.  Human Blood Groups.  3^rd edition, 2013, Wiley-Blackwell, page 286, Section 7.4.1, "Anti-Kp^a can cause delayed HTRs; only one case is reported as serious."  He goes on to say, "Owing to the relative rarity of Kp^a, anti-Kp^a, and serious clinical sequelae of incompatible transfusion, Kp(a+) red cells are not required in antibody screening panels."

 

The "severe" case was that of Koshy R, Patel B, Harrison JS.  Anti-Kp^a-induced severe delayed haemolytic transfusion reaction.  Immunohematology 2009; 25: 44-47, which, as I have stated before, and with apologies to the authors, I find difficulty in understanding the use of the word "severe".

 

The reference cited for the second quotation is Garratty G.  Screening for RBC antibodies - what should we expect from antibody detection RBCs.  Immunohematology 2002; 18: 71-77.

 

In addition, and also written by Geoff Daniels, the Controlled Document used by NHSBT (SPN214/3, effective 12/01/15)  The clinical significance of blood group alloantibodies and the supply of blood for transfusion, it states, for Kell Blood Group System Antibodies, "All Kell antibodies (except anti-Kp^a, -Ul^a and -K17) - my bold font - Antigen-negative red cells.

 

Anti-Kp^a, Ul^a, -K17 - (if detected by IAT at 37^oC) - select red cells compatible by IAT at 37^oC.

 

For these antibodies previously detected but not detectable in current sample - select red cells compatible by IAT at 37^oC.

 

This Controlled Document, I was surprised to find, is available on Google.

 

I doubt very much if either the late, and much lamented Professor George Garratty, or Dr. Geoff Daniels (who, incidentally, and sadly, is retiring tomorrow) would expose themselves to possible legal proceedings (should others follow their advice and the patient suffers) unless they were pretty certain that what they were saying was safe and neither, I might add, would NHSBT!

 

       

[Auntie-D]

I doubt very much if either the late, and much lamented Professor George Garratty, or Dr. Geoff Daniels (who, incidentally, and sadly, is retiring tomorrow) would expose themselves to possible legal proceedings (should others follow their advice and the patient suffers) unless they were pretty certain that what they were saying was safe and neither, I might add, would NHSBT!

 

       

 

Oh I'm not saying they're not safe, just that they will be destroyed earlier than if the antigen wasn't present - and we are wanting to reduce donor exposure and frequency of appointments for thal patients. For a post op patient or top up, then I wouldn't have even asked the question.

 

I would also like to add to the mix that this patient is only 4 and has a lifetime to develop more antibodies...

[David Saikin]

You mean phenotyping the units? We only have basic phenotyping cards/reagents

You can buy anti-Kpa; it works in gel, you just have to validate it at your facility.  I have a few area pts who get transfused and have this ab

[Malcolm Needs ☆]

Oh I'm not saying they're not safe, just that they will be destroyed earlier than if the antigen wasn't present - and we are wanting to reduce donor exposure and frequency of appointments for thal patients. For a post op patient or top up, then I wouldn't have even asked the question.

 

I would also like to add to the mix that this patient is only 4 and has a lifetime to develop more antibodies...

 

True, but that is most unlikely to happen.

 

With regard to your second point, that is true of all transfusion dependent patients (particularly sickle cell patients in the UK, as most of our donors are from White populations, and they will be transfusion dependent from almost day one - if I ignore the HbF phase).  We have patients with more than seven antibodies (who would be untransfusable if we tried to get antigen negative blood to cover all of the antibodies - but we don't because we know which of these are i) still detectable and ii) which of the ones that are still detectable are also clinically significant).

 

Sad as it may seem, eventually one has to be pragmatic, rather than dogmatic about these things.

[StevenB]

Not to make light of your situation, but if you do happen to transfuse a Kp(a+) cell and there is a response, you most likely will have resolved your situation for future transfusions.  If that were to occur, I'd freeze whatever remaining serum or plasma you had from this patient.  If in the future the antibody were to drop off again, use the frozen sample to do a "compatibility check" on the units you intend to transfuse.

 

I was going to suggest that in the future, anytime you see a Kp(a+) cell or other lows on your panels, remove the cell from the test.  But with the way the manufacturer's are stacking the panels with lows, you'd lose half of your panel!  And if you are seeing lows on your screening cells, I'd recommend sending them a nasty gram expressing your displeasure at having lows on screening cells!

[Auntie-D]

Not to make light of your situation, but if you do happen to transfuse a Kp(a+) cell and there is a response, you most likely will have resolved your situation for future transfusions.  If that were to occur, I'd freeze whatever remaining serum or plasma you had from this patient.  If in the future the antibody were to drop off again, use the frozen sample to do a "compatibility check" on the units you intend to transfuse.

 

I have actually considered this

[R1R2]

me too.  

[SMILLER]

Our reference lab has a standing request that we send them things like plasma from patients making anti-Kpa or whatever.

 

Scott