any Idea?

[sassai13]

Hello, everybody!

I have interesting specimen of pacient in our lab. Patient is A, Rh D+, we do crossmatch (gel) with two donors and we get in NaCl technic - gel (with adding bromelin) negative and in LISS/Coombs tehnic (AHG) positive. We do ICT and autocontrol and they were all positive. We do also antibody screening with test cell reagents treated with papain and antibody screening with test cell adding bromelin and there were ALL NEGATIVE!!

As I mentioned before autocontrol was positive, but DAT was Negative!

I don't have any idea left what to do...any suggestion? :cool:

Thanks in advance!

Sasa

[Yanxia]

When DAT is neg and autocontrol is pos, I think we can get this kind of result in two case, one is autoantibodies on cells is less and the other is false result.

In enzyme technique the screening result is neg and in AHG it is pos, I think it maybe because the complements or the antigen is destroyed by enzyme.

Edited November 26, 2008 by shily
spelling error

[sassai13]

Thank you Shily for your answer. We did autoadsorption, cause the patient didn't receive any transfusion, and the ICT was the same like with native plasma.

We found that it might be sth. in this plasma which nespecific react with our dilution reagent (LISS) and with LISS/Coombs card (gel). When we did suspension in NaCl the autocontrol was neg. Also ICT in tube test was neg.

Have a nice day,

Sasa

[galvania]

Yes, this sounds like the patient is reacting with something in the LISS reagent. This is rare but it does happen occasionally. Because the screening cells are in a different buffer, you can get positive crossmatches (or auto-controls) and negative antibody screens. I am a bit puzzled as to why the DAT was negative though - surely the cells were also suspended in the same LISS diluent?

Interesting to see that you are still doing crossmatching using enzymes. Is this the case in the whole country? I don't know anyone else in Europe who still routinely uses enzymes in the crossmatch. Most don't use enzymes at all routinely.

[sassai13]

Yes, this sounds like the patient is reacting with something in the LISS reagent. This is rare but it does happen occasionally. Because the screening cells are in a different buffer, you can get positive crossmatches (or auto-controls) and negative antibody screens. I am a bit puzzled as to why the DAT was negative though - surely the cells were also suspended in the same LISS diluent?

Interesting to see that you are still doing crossmatching using enzymes. Is this the case in the whole country? I don't know anyone else in Europe who still routinely uses enzymes in the crossmatch. Most don't use enzymes at all routinely.

Hello Anna,

Thanks for your answer.

After treating red cells and also plasma, we made conclusion that it must be sth. which reacts unspecific (and not antibodies).

Yes, we still do crossmatches using enzyme technic, we (not me!) didn't decided to go on "type and screen" , so I believe when you say, that we must be the last in Europe. ;-)

Have any really nice day,

Sasa

[Kip Kuttner]

We are working on a patient who is K negative and who has been receiving K negative units since sensitization 6 months ago. The DAT is Positive with IgG and polyclonal reagent. C3 is negative.

A panel shows a clean reactivity pattern for anti-K. In addition we are able to elute an antibody that reacts like K in a panel. If the eluate is adsorbed to remove the "anti-K" reactivity disappears. In fact, there is no other reactivity.... no cold or warm auto antibody. All other common antibodies have been ruled out.

The patient is 62 and being treated for cancer. The patient is not being treated with antibiotics.

I understand the anti-K in the neat serum, but not the eluate. I suppose there could be nonspecific absorption of the antibody to the red cells, but why?

Thanks

[Yanxia]

The DAT positive patient, some include antibodies have real specificity and others are mimicking antibodies. And the mimicking antibodies can be adsorbed by the antigen positive and negative cells( all or partial). It can be divided into two kind of antibodies, one is the antigen present on the patient's cells ,the other is the antigen is not present on the patient's cells.

I think this patient maybe have the later mimicking antibodies. To prove this conclusion we can use some K negative red cells to adsorb the patient's serum or the patient's eluate, if we can remove all or part of the reactivity, then the guess is right.

Sorry for my poor English, if it bring you some trouble to understand .

Edited April 14, 2009 by shily
spelling mistake

[galvania]

Probably a silly question - but did you actually double-check all the units of blood that she received to make sure they really were K-? If the positive DAT is due to a 'rogue' unit of blood, then if you're doing the DAT in gel, you might well see a double population. Another silly question - when you did the eluate, did you check the last wash tio make sure that you weren't still picking up allo-antibody? Another idea - could it be that the cancer that this patient is suffering from is altering some clones of her red cells so that they are now able to uptake her anti-K. Is she still grouping as completely K-? A bit far-fetched, but has she got some sort of bacterial infection which is being recognised by her anti-K, with the resulting immune complexes being absorbed on to her red cells? Or it could be non-specific uptake of antibody.

I'm sure there are lots of other possibilities that I haven't thought about.....

[David Saikin]

I had a patient years ago with anti-K. He always rec'd K= red cells. He always had a positive DAT with only anti-K in the eluate. We could not even attribute this to the Matahasi-Ogata phenonmenon because there were no other antibodies found in the eluate (so how could the anti-K be "trapped" when the non-existent other antibody attached?). We saw him for 3 years . . .

[jbporter]

Yes, this sounds like the patient is reacting with something in the LISS reagent. This is rare but it does happen occasionally. Because the screening cells are in a different buffer, you can get positive crossmatches (or auto-controls) and negative antibody screens. I am a bit puzzled as to why the DAT was negative though - surely the cells were also suspended in the same LISS diluent?

Interesting to see that you are still doing crossmatching using enzymes. Is this the case in the whole country? I don't know anyone else in Europe who still routinely uses enzymes in the crossmatch. Most don't use enzymes at all routinely.

Were you referring to the patient's own cells (DAT) being suspended in LISS?

jbp

[sassai13]

Were you referring to the patient's own cells (DAT) being suspended in LISS?

jbp

we did DAT, treating patient's cell using Liss, because it was negative we were a bit confused..

[jbporter]

Is LISS needed for a DAT?

[sassai13]

Is LISS needed for a DAT?

this is manufacturer's instructions for DCT on gel card..which we are using..

Have a nice day,

Saša

[jbporter]

I haven't used gel--just tube DATs. Thanks for the explanation.

jbp.

[sassai13]

I haven't used gel--just tube DATs. Thanks for the explanation.

jbp.

Not at all, JBP. Thanks for your remarks.

Have a nice, smilling day,

S.

[galvania]

This might be relevant to your case. I've just read a paper in a recent 'Transfusion' which talks about 2 subjects who grouped as K- (suspicion was aroused because one had a very weak trace reaction with human anti-K in DiaMed gel) but were actually K+. They were both Kpa+. Maybe you should go back to your donors and check their Kpa type. If they are positive, you might have one of these 'special' Ks. I don't have the copy of the paper to hand, but if you're interested I can put the details on te next time I post

[galvania]

Me again. The paper is in vol 49, no.4, April 2009 and is entitled: A novel KEL*1,3 allele with weak Kell antigen expression confirming the cis-modifier effect of KEL3.

Both cases were really KEL:1,2,3,4 (Kk, Kpa+b+) but grouped as K- because the presence of the Kpa modified the expression of the K.

This was certainly new to me. I had often heard of (and seen) the presence of Kpa weakening the k antigen, but not the K

[PammyDQ]

I had a patient years ago with anti-K. He always rec'd K= red cells. He always had a positive DAT with only anti-K in the eluate. We could not even attribute this to the Matahasi-Ogata phenonmenon because there were no other antibodies found in the eluate (so how could the anti-K be "trapped" when the non-existent other antibody attached?). We saw him for 3 years . . .

In my career I too have seen 2 patients with this same phenomena. It went on for years for each patient...both had anti-K, always recieved Kneg units, always had +DAT with anti-K in their eluate. There was never any evidence of hemolysis.