Filtering Patient Plasma?

[kwm5321]

Does anyone filter patient plasma?

Not routinely, but when testing reveals only non-specific reactions and all clinically significant antibodies have been ruled out? What size filter is used? Could you give me the specifics for the filter that's used (where to purchase)? Could clinically significant antibodies be removed when filtering? Thanks.

[Malcolm Needs ☆]

We never filter patients' plasma, and I have never heard of this way of getting rid of auto-antibodies before.

Would you mind expanding on this a little for an ignorant idiot?????????

:confused::confused::confused:

[L106]

I haven't heard anything about this. (Gee, wouldn't it be GREAT if we could just "filter-away" patients' antibodies??!!)

[Malcolm Needs ☆]

I haven't heard anything about this. (Gee, wouldn't it be GREAT if we could just "filter-away" patients' antibodies??!!)

NO!

I'd be out of a job!!!!!!!!!!!!!!!!!!!!!!!!!!!!

....and then who would Rashmi (RR1) insult?????????

:eek::eek::eek::eek::eek:

[kwm5321]

I have not personally done this either.

I sent a specimen to our local blood supplier reference lab and was told that their testing had revealed some nonspecific reactivity by multiple methodologies. They couldn't determine what it was so they 'filtered' the plasma and the reactivity went away.

??????

I had never heard of such a thing so I submitted the question.

I don't know if it's a really good thing or really bad thing or if it's somewhere in-between, so I asked for others help.

Thanks for your response.

[Smarty pants]

I haven't heard of this, and can't imagine a filter small enough to remove the antibodies. Even a dialyzer doesn't remove IgG. I wonder if they used a platelet filter to remove the WBCs?? (which doesn't really make sense either, cuz they don't survive the freezer) Fascinating...

[Malcolm Needs ☆]

I know I shouldn't say this kwm5321 (not knowing the details) but I just wonder if the Reference Laboratory were having you on a bit of string, and trying it on; suggesting that you and your team wouldn't know that what they were saying was untrue.

I've known of (stupid) Reference Laboratories do this in the past I'm ashamed to say.

[kwm5321]

No, they even gave me the filter number if I want to order some.

[Malcolm Needs ☆]

Wow! That's pretty conclusive then.

I apologise to them.

[adiescast]

I have heard of a type of column absorption "filtering system" that had the capability of attracting antibodies out of plasma. I don't remember the exact specifications. This was several years ago and I have not heard much about it since then, so it may either have not worked or not been feasable for production. The person who told me about it was looking at it as a way to remove antibodies in situations where no compatible blood could be found in order to reduce the likelihood of a transfusion reaction when incompatible blood must be given.

[Malcolm Needs ☆]

I have heard of a type of column absorption "filtering system" that had the capability of attracting antibodies out of plasma. I don't remember the exact specifications. This was several years ago and I have not heard much about it since then, so it may either have not worked or not been feasable for production. The person who told me about it was looking at it as a way to remove antibodies in situations where no compatible blood could be found in order to reduce the likelihood of a transfusion reaction when incompatible blood must be given.

I know that affinity columns are used to reduce ABO antibody titres in ABO incompatible renal transplants, and so I suppose these could be used in the Laboratory to adsorb out antibodies (very expensive way of doing it, I might add), but these would be non-specific (e.g. would take out all IgG antibodies) and so would adsorb out alloantibodies as well as auto-antibodies, which would be dangerous in the extreme.

:confused::confused:

[David Saikin]

There was a Protein S filter (I think) years ago . . . we used to put in line on our apheresis machine to attempt to absorb out auto antibodies (it cost $5000/use). It was rarely successful and only offered short-term relief - the patients ALWAYS expired.

[L106]

In the early 1990's we had several experiences with a product called "Prosorba" (by IMRE) that was designed to remove IgG and IgG-containing circulating immune complexes, primarily to treat ITP patients. (We had mixed results with it; the most successful case was a schnauzer from a local veterinarian clinic!)

But I haven't heard of anyone using this product for many years (and I've never heard of it being used as a reference laboratory tool.)

[Malcolm Needs ☆]

We had mixed results with it; the most successful case was a schnauzer from a local veterinarian clinic!

Perhaps you should have been more dogged with your validation with human plasma?????????

:eek::eek::eek:

Sorry, horrible pun, but it had to be made.

[adiescast]

Malcolm, you are incorrigible!

I think the Prosorba column was what I was thinking of in my earlier post. It just never took off.

[clmergen]

Prosorba columns are no longer being used in the US as of about 3 years ago. I know our Apheresis department had a patient that it worked wonders on. I think the patient had Myasthenia Gravis.

[kate murphy]

About 15 yrs ago, we had a transfusion dependent 48y F with several alloantibodies and one very potent autoantibody. In conjunction with the Heme Fellows, we tried everything we could - plasma exchange, canvasing the country for compatible blood, chemotherapy, etc. Nothing worked - she would hemolyze all transfused blood within days.

We finally plasma echanged through a Prosorba column 3 times followed with a cytoxan chaser. Her hemolytic anemia has not returned - she still sends us Christmas cards. I believe the column was Staph Protein A. Unknown mechanism of why/how it works. Other centers reported bad (anaphylactic) reactions to the Staph Protein. For our one and only patient it was a miracle.

[L106]

Kate, that's good to hear about your patient who was dramatically helped by the Prosorba column. Many patients were not helped, and some experienced adversed reactions, as you mentioned. I'm sure the unpredictable results are the reason it was taken off the market.

[TimOz]

I have an alternate theory. I think the original post is asking about syringe end filters to remove fibrin from the sample to reduce fasle positive reactions due to fibrin in column systems (not autoantibodies). I have done this with really turbid, hopeless, frozen and thawed samples and it works.