Plasma Vol in PLT Pheresis

[vav5325]

At our facility (800 beds,Trauma 2 ) we often give ABO incompatilbe PLT Pheresis to our pts. Ive noticed that there is 150ml to 350 ml of plasma in each plt. Thats the same amount of plasma in our FFP. Why do our pts not have more of a "reaction" to these plts? We've had some with weakly positive DATS but thats it. Just curious.

[Malcolm Needs ☆]

There are two reasons that immediately come to mind.

First is the titre (particularly the IgG titre) of the ABO antibodies in the plasma.

Secondly, and probably much more importantly, is the stature/circulatory volume of your patients. The affect of transfusing high titre anti-A plasma to a group A neonate, for example, would be much more serious than giving this to an adult, even taking into account the poor development of the neonate's complement system and their A antigen.

Almost all of the serious/fatal cases of acute/fatal haemolytic transfusion reactions due to transfused ABO antibody in the past few years have involved neonates/babies.

I'm not saying that these are the only reasons, but they do have to be taken into account.

[vav5325]

Yeah we give our neonates ABO compatible PLT pheresis. The circulatory volume in adult pts makes sense but we wouldnt give an A pos patient B FFP because of the Ant-A in the plasma. Where has we wouldnt hesitate to give the same A pos patient a B PLT pheresis. Could it be that the concentration of plts in the pheresis is high enought to offset the titer of the ABO antibodies in the plasma?

[Malcolm Needs ☆]

You could well be right there vav5325, but I would be alter to not getting the platelet increment you expect if you are giving B platelets to an A recipient, on the grounds that, although platelets do not inherently express ABO antigens, they do adsorb Type 1 ABO antigens from the plasma and, if the donor is a secretor (particularly if they are from the Black population (who have a more active D-galactosyl transferase than do White donors) and if the recipient has a high-titer anti-B, the transfused platelets may well be destroyed in an accelerated way, thus the increment is not what you might expect - nothing dangerous though in most cases.

[RR1]

In the 2007 UK SHOT (Serious Hazards of Transfusion) report there was a case of acute haemolytic transfusion reaction, resulting in major morbidity, following an ABO-incompatible platelet transfusion.

www.SHOTuk.org

[Malcolm Needs ☆]

You could well be right there vav5325, but I would be alter to not getting the platelet increment you expect if you are giving B platelets to an A recipient, on the grounds that, although platelets do not inherently express ABO antigens, they do adsorb Type 1 ABO antigens from the plasma and, if the donor is a secretor (particularly if they are from the Black population (who have a more active D-galactosyl transferase than do White donors) and if the recipient has a high-titer anti-B, the transfused platelets may well be destroyed in an accelerated way, thus the increment is not what you might expect - nothing dangerous though in most cases.

Or even "alert"!!!!!!!!!!!!!!!!!

Honestly, my spelling!!!!!!!!!!!!!!!!!!!!!!!!!!!

:redface::redface:

[vav5325]

Im more interested in whats going on in the body of adult patients. Ill give two examples:

1 - 40 year old male who has an ABO of A pos receives 1 unit of FFP that is B. Clearly he is going to have a severe haemolytic reaction. The FFP has about 280 ml.

2- Same 40 year old male received 2 plt pheresis about 8 months ago. One PLT was O while the other was B. Both PLTs had about 200 mls of plasma. No adverse reaction.

Scenario 2 happens all the time in our facility. So more ABO incompatible plasma was given in scenario 2 then in scenario 1. NO reaction in the 2nd but a severe one the 1st Am I wrong to think that there will be a reaction in scenario 1? Ive always treated FFP and Red Cells equally in terms of haemolytic reactions. Just trying to figure out whats the difference when infusing platelet pheresis then FFP when plasma amounts are the same.

[RR1]

As Malcolm stated earlier, it depends on the anti-A and anti-B titre. In the UK, guidelines state FFP from group A or B donors can be used for A or B recipients as a second choice, as long as they are HT negative.

Group O FFP can only ever be given to O recipients regardless of HT status.

So in your first scenario you may not have a reaction.

[Malcolm Needs ☆]

Im more interested in whats going on in the body of adult patients. Ill give two examples:

1 - 40 year old male who has an ABO of A pos receives 1 unit of FFP that is B. Clearly he is going to have a severe haemolytic reaction. The FFP has about 280 ml.

2- Same 40 year old male received 2 plt pheresis about 8 months ago. One PLT was O while the other was B. Both PLTs had about 200 mls of plasma. No adverse reaction.

Scenario 2 happens all the time in our facility. So more ABO incompatible plasma was given in scenario 2 then in scenario 1. NO reaction in the 2nd but a severe one the 1st Am I wrong to think that there will be a reaction in scenario 1? Ive always treated FFP and Red Cells equally in terms of haemolytic reactions. Just trying to figure out whats the difference when infusing platelet pheresis then FFP when plasma amounts are the same.

vav5325, it is not the volume of ABO incompatible plasma that is transfused in this case.

What is important is the anti-A titre, particularly the IgG anti-A titre, that is important. This why plasma, either in the form of FFP, or in the form of a suspending medium for platelets, should always be tested for high titre ABO antibodies and, what is more, the donor should be recorded as "dangerous" in such a situation (e.g. must only be used for group O or group A patients).

[Malcolm Needs ☆]

Thanks Rashmi.

You type quicker then I do!

[L106]

It is true that the results are not always predictable. I am aware of a situation where an entire unit of Group O Fresh Frozen Plasma (325 mls) was transfused to a 70 year old Group A female patient and she experienced absolutely no apparent adverse effects.

[Malcolm Needs ☆]

It is true that the results are not always predictable. I am aware of a situation where an entire unit of Group O Fresh Frozen Plasma (325 mls) was transfused to a 70 year old Group A female patient and she experienced absolutely no apparent adverse effects.

The same is true for red cells.

I am aware of at least two occasions when more than one unit of ABO incompatible blood has been transfused to a patient with absolutely no immediate problem whatsoever, and no clinical sequelae.

BUT I, for one, would not like to take this chance, on the grounds that a) I enjoy my job (and don't want to lose it) and I enjoy my freedom (and, again, don't want to lose it by doing a 30 year stretch)! I also, of course, have a certain amount of respect for the patient's immune system.

[vav5325]

Thanks for the responses...very helpful:) As you can tell I'm fairly new in the field of Blood banking (just graduated a couple of years ago). Thanks again

[janet]

We went to platelet pools here in Canada a while back (4 platelet donations pooled into one of those donor's plasma). Before the switch I had read and was told we may have a greater chance of reaction when giving incompatible blood groups (as there is when giving an apheresis unit).....I was a little worried, read about some institutions that titre before giving or plasma reduce if incompatible - but we took a 'wait and see' attitude. Well the waiting brought about a hemolytic reaction for a 50 some year old man with myelodysplastic syndrome and coronary disease. The physician happened to be present when he reacted - she said it was so classic - the back pain, fever, burning, etc (along with chest pain...?the stress and pre-disposition to cardiac symptoms?). Thank goodness he recovered after a couple nights stay in hosptital voiding bright red urine!!! Now we titre any incompatible platelet before issue (we don't have the option of plasma reducing).

There is no concensus about what the cut off titre should be ... I have read various articles. One European (I think) blood centre titres all the plasma they use to make pools and use 128 IgM as their cut off. We went with 64 IgM because that what was in a few of the articles I read and we wanted to be safe after having a close call.

BTW the titre of the platelet the patient who reacted received was 128 IgM ... I tested 20 plasmas in validating my method and only 2 had high titre Anti-As (greater than 64) and no Anti-Bs. We try to keep group A platelets since they would be compatible with the majority of people, if the unit we want to give has a high titre and we don't have an alternate unit to give we get the physician's approval before giving it (hasn't happened yet).