Hello, 

I  have a case of an anti-Yt b been identified by our Reference Lab and I'm struggling to find out its clinical significance given its rarity. Does anyone know if it has been implicated in transfusion reactions? The intensivist says the patient is clinically showing signs of hemolysis, (Raised LDH and lowered haptoglobin). 

Many thanks!

Kelli 

 

Hi Kelli,

Reid ME, Lomas-Francis C, Olsson ML, The Blood Group ANtigen FactsBook, 3^rd edition, 2012, Academic Press, states that anti-Yt^b causes neither haemolytic transfusion reactions, nor HDFN.

Daniels G, Human Blood Groups, 3rd edition, 2013, Wiley-Blackwell states more or less the same (but does state that monocyte monolayer assays do predict the possibility that some examples of anti-Yt^b could cause premature red cell destruction, but not a clinically significant haemolytic transfusion reaction).  It should be noted that the MMA is no longer performed, to any great extent, in the UK, as it has been found to be unreliable.

If you put "Daniels Clinical Significance of Red Cell Antibodies" into your search engine, one of the things that springs up is an NHSBT Specification Document, written by Geoff, entitled "SPN214, Clinical SIgnificance of Blood Group Alloantibodies.", in which Geoff says that it is safe to give cross-match compatible blood to a patient with anti-Yt^b, rather than get Yt(b-) blood.  It is a useful document to download.

Carolyn Giles, who discovered anti-Yt^b, and with whom I had the huge honour to work with when I was younger (and more junior), never regarded the antibody as clinically significant.

I would suggest, therefore, that the raised LDH and lowered haptoglobins is either a coincidence, or evidence of a subclinical haemolytic transfusion reaction (i.e. the red cells may not be lasting as long in the circulation as may be expected, but their destruction is slow and is not causing a clinically significant haemolytic transfusion reaction).

I hope that helps.

Great reference - thanks Malcolm!

Thank you so much Malcolm. The intensivist was also querying mechinical destruction by the heart, so now that they know the anti-Ytb is unlikely to be the cause of the low grade hemolysis, they are going to do some cardiac investigations. Excellent references and once again Malcolm is the veritable font of information. 

On 01/04/2016 at 4:25 AM, Kellimq said:

Thank you so much Malcolm. The intensivist was also querying mechinical destruction by the heart, so now that they know the anti-Ytb is unlikely to be the cause of the low grade hemolysis, they are going to do some cardiac investigations. Excellent references and once again Malcolm is the veritable font of information. 

What was the outcome Kellimq?  Was it mechanical destruction, or do they still not know?

The patient has had a mitral valve repair and then CABG (now post-op day 5). Day 53 in ICU.  The hb now appears to be stabilising. They are still monitoring her, but are hopeful they have found the cause of the hemolysis.

 

53 minutes ago, Kellimq said:

The patient has had a mitral valve repair and then CABG (now post-op day 5). Day 53 in ICU.  The hb now appears to be stabilising. They are still monitoring her, but are hopeful they have found the cause of the hemolysis.

 

Brilliant - thanks for that.