warm or cold autoantibodies

[Mini Me]

Hi all

This afternoon we had this patient whose results were hard to absorb for me. Patient's screening cells (ortho 3 cell 0.8%) all positive (2+). so I went ahead and set up panel, all the 11 panel cells were positive (2+) including autocontrol.

DAT (Broadspectrum) positive.

Eluat all cells Positive

we sent this work to refrence lab but was still thinking about it. Any openions on this ?

[David Saikin]

Sounds like an autoimmune process . . . you may have tried to autoabsorb out the antibody. The 2+ gel reaction would only be w+ at best in tubes. My suggestion would be to perform a Peg autoabsorption and do all your work in tubes. If the patient has been transfused within the past 3 months, you should not perform the autoabsorption. Also, may want to transfuse Rh phenotype specific red cells to prevent any Rh sensitizations while this process is active.

[asimard]

Hi David,

Can you explain how you do your PEG autoabsorption?

[Mini Me]

Thanks David for your reply.

It turned out to be cold autoantibody. But I was qurious that how would I differentiate between cold and warm autoantibody while I was performing the abtibody ID by Gel system.

Also i would be interested to know about PEG autoabsorption too.

Thanks Again

[galvania]

Thanks David for your reply.

It turned out to be cold autoantibody. But I was qurious that how would I differentiate between cold and warm autoantibody while I was performing the abtibody ID by Gel system.

Also i would be interested to know about PEG autoabsorption too.

Thanks Again

Wasn't the auto-control positive when you did your blood group??

[David Saikin]

In a nutshell - Peg autoabsorption is equal volumes of cells/peg/plasma. incubate for 15-30 minutes. centrifuge/remove supernatant. to test use 4 drops of supernatant (it is peg and plasma) and no other additives. test for presence of autoab as per antibody testing (37C incubation 10-15 min, 4 saline washes. anti-IgG, neg rx use check cells).

[Mini Me]

Yes My autocontrol was 2+ positive

Thanks for Reply

Mini Me

[galvania]

Yes My autocontrol was 2+ positive

Thanks for Reply

Mini Me

Well unless you are using enzyme techniques, or reagents with a very high albumin content to do your blood grouping, a positive auto control in the grouping is almost always due to cold auto-antibodies. Warm auto-antibodies don't give positive auto-controls in a direct agglutination technique.

Just to be sure we are talking about the same control, I am assuming you are using something like the following: Anti-A, anti-B, anti-D, control. It is this control that I am talking about, not the auto control in the Coombs technique

Anna

[mrstymt]

darn i wished i saw this thread before answering this question wrong the other day. at least i knew that i had to send it to reference

[marilynm]

You need to get a real good history on the patient, especially previous and/or recent transfusions.

If the patient has not been recently transfused, then you have a warm reactive autoantibody and can do a ZZAP autoadsorption. If not, then adsorptions with selected cells will need to be done.

I might make a cautionary comment about PEG adsorptions. There are several papers listing the limitations for PEG adsorptons where weak antibodies have been missed by this technique. We never started using it in my days at Gamma because of this. We were one of the first labs to write a response to the first Letter to the Editor of Transfusion on this subject.

Marilyn M

PS If you are interested in the references I can get them for you.

[tbostock]

Usually in gel, a cold autoantibody reacts weaker than a warm auto (these are usually 4+ in every cell); not always though. We usually do a screen in tube at immediate spin, 5 mins at RT, and 5 mins in the refrig. That will usually distinguish cold from warm. Also, sometimes when everything is positive, including all cells in the elution, it can be medication related. So, as stated above, a full patient history can be helpful.