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Adsorption/Absorption


Bertie

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George Garratty, to name but a few).

I had the distinct pleasure of attending a teleconference last Wednesday given by Dr Garratty. He is doing a series every Wednesday for the next several months. Unfortunately I cannot attend tomorrows teleconference--but I plan the make the others. He is amazingly knowledgeable and the infortmation he presented on auto antibodies was nothing short of brilliant.

I recommend to all of you who might have the opportunity to join in the teleconference series to do so. They are from 8:30am-10:30am each Wednesday. I am not sure how to access the conferences, but I know he is working at the ARC in Paloma, California. Perhaps one could get information through a link or something. Like I said, I'm not sure.

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I have a recipe somewhere for making stroma from a donor unit. Unfortunately, it is not in electronic format, so I can't share it at the moment. Lately we have been saving up reagent screening cells and doing PEG adsorptions with them instead. Preparing stroma from 3 units of red cells was a day and a half chore that I really don't have time for right now.

We are currently looking into doing PEG adsorptions. Do you have a procedure for that you can share?

Thanks in advance.

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In a hospital, maybe you have a unit that is returned to the transfusion service that was not all used up, or some left from splitting for a baby, etc. Expired units can be used for adsorption. The problem is that you need to type the units for Rh, Kell, Kidd, Duffy and Ss (only for Rh, Kell and Kidd if you use enzyme treated cells). You may not have the typing reagents, or enzymes, if you are a small lab.

However, with that wonderful explanation Malcolm gave, you at least will understand the technique and why it might take your reference lab a day for two to get blood for your patient!!

marilyn m

PS Absorption is still used it we want to remove a certain antibody from a plasma, and this is accomplished by adsorbing it with a cell having the corresponding antigen.

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I had the pleasure of seeing Dr. Garratty speak a couple years back...

however, I am googling ( no, not drooling) like mad and not finding anything about this teleconference series...

I see your location is CA. Perhaps you can contact the ARC reference lab directly for information?

Or if you send me your e-mail address I will gladly forward you the information I have.:)

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  • 9 years later...
On 4/12/2010 at 8:16 PM, Malcolm Needs said:

It is important to remember, at this stage, that most (but not all by any means) auto-antibodies are directed against Rh antigens.

Is this mean autoantiboody absorbed better with Rh antigen? 

I am also trying to understand  how RCI deal with pan-reactivity especially with HFA

Edited by gagpinks
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The Rh antibody specificities involved in WAIHA are usually something like anti-Rh17 or anti-Rh18, which are antibodies that are directed against antigens that are almost expressed universally on all human red cells, except those of very rare individuals with deletion or partial deletion of Rh antigens.  That having been said, these antibodies very often mimic other specificities, such as, for example, an auto-anti-e, but can be adsorbed to extinction by red cells apparently not expressing the antigen.  In other words, the apparent auto-anti-e can be completely adsorbed by using DcE/DcE (R2R2) red cells that are, of course, e Negative.  This is because the DcE/DcE (R2R2) red cells will express both the Rh17 and Rh18 antigens, which are the antigens that the auto-antibody specificity is actually directed.

There are other specificities that can be involved in WAIHA outside of the Rh Blood Group System (such as auto-anti-Wrb), but these are much rarer.

As far as your second point is concerned, I attach three PowerPoint slides.  The first is a diagram of how we go about looking at antibodies, the second is a photograph showing the store of some 400 rare red cells frozen down for use in RCI investigations, and the third is a (very untidy looking - but we know where everything is located) freezer full of very rare antisera, so that we can "attack" a problem from both sides, if necessary, by looking at the antibody in the patient's plasma, and/or the (usually) high prevalence antigen lacking from the patient's red cells.  Armed with information, such as the ethnicity of the patient (not politically correct these days, but HUGELY important), and how the antibody reacts with red cells treated with various enzymes and chemicals, we can narrow down the specificity without having to use, and possibly waste, a large number of different rare red cells and antibodies.

Antibody algorithm..ppt

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