The plot thickens.....

[lauried01]

This refers to my earlier thread about the lady with the anti-c that we gave unxm'd c-pos units to- here we are almost 2 weeks later- her DAT is now 1+ macroscopically positive- we repeated her ABID on a new sample- and she appears to have developed anti-E!?! Interesting, considering all the units she received, even the unxm'd were all E neg. We have gone back and repeated EVERYTHING we've done, from initial RzR1 cells to rule out anti-E(initially negative- new sample from 10-7- 2+ at 37 and AHG). Everything checks out- no way we could have stimulated an Anti-E, and it definitely wasn't there on admit. WTH?

We are probably gonna have to send this to Puget Sound for an elution and whatever else to figure this out. We were thinking maybe she's developed a warm auto that is mimicking anti-E- what do you guys think?

The snow is fallin' in Anchorage, and roads are slick- better stock up on that O neg;)....

Oh man, the thought just occurred to me- she got 2 Platelet Pheresis- could she have gotten enough RBC's from those to have developed Anti-E?!(I thought Pheresis Plts. were pretty clean)

Edited October 10, 2008 by lauried01
I had an epiphany....

[David Saikin]

Your patient may have had an anti-E that was not identified previously, but why it should decide to become detectable now is a good question. Your comment on the Plt transfusions may have hit the nail on the head, ie, provided the antigen to activate the clones. I am curious as to whose reagents were used to type your units for E. Recently I had a patient that with one company's anti-e was negative and 3+ using a different manufacturer's product. Interesting, esp since heterozygous controls were definitely reactive. (This patient has been sent for molecular analysis).

[galvania]

I would go for a mimicking antibody. I'm sure I read somewhere that auto-antibodies can get sort of 'confused' to begin with then settle down into something more specific...I would test again in a couple of weeks - DAT and antibody screen; and if the DAT is still pos then do an eluate

[lauried01]

Dave,

We are using Immucor Anti-E monoclonal. I am not sure if we even have any old expired Anti-E to do a double check, and our higher-ups don't care much for Ortho (fine with me- I used to work for Gamma years ago- I'll always be partial). I am gonna talk to our TS Pathologist when he comes in- as it stands, now, we are sending this out today for elution and ABID. She has had so many units of blood in the past few years, she coulda easily developed an E, and it might have fallen below detectable limits, 'til a little stimulus. Nice theory, eh?

Sure would be nice to get to the bottom of this, before she comes in needing more "STAT" transfusions!

[Lcsmrz]

It could be that the patient had an Anti-E all along, just below detectable limits. Any contact with an E postiive cell (RBC or PLT) may have caused a quick amnestic response.

Also, with many trauma patients, they are rather diluted out with crystaloids on arrival, and the "diluted" sample may have dropped a weak antibdy below detectable limits.

Because Anti-c and -E tend to go together, many sites give R1R1 cells to patients with either.

Inteeresting case !!!

[lauried01]

That is our procedure, as well (giving c neg, E neg), to try to diminsh the development of an antibody in a known responder- I did talk to our path about the possibility of this scenario- platelet pheresis are supposed to be pretty clean, but I guess it wouldn't take too many cells to elicit a secondary response. He did agree that it is possible.:cool:

The other option, being that of a mimicking auto, is also still a possibility- we'll know more when we get the results back from Puget Sound (our reference lab for such problems). I work tomorrow and Sunday, so chances are we'll get a prelim back on one of my days off (Mon. thru Wed.)- I can hardly stand the suspense!

Just another prime example of why I love what I do...

[Yanxia]

Maybe we can use CCdee cells to absorb the antibodies in the patient's serum, and then do elution testing . If the anti-E can absorbed by the antigen neg cells , then it is mimiking antibody.

[lauried01]

Well, we got the ID back- Anti-c (no shock there), -E, and Sda. So, the big E is there, but how- since we gave all E neg? Maybe my platelet theory is correct....

Now I am off for a few days (good thing, too, because the roads are really bad- people sliding off the hwy-quite snowy)-so I guess we'll wait and see what else pops up when I go back. We saved the cell suspensions from the units she received- we retyped 'em like 3 times, but the thought occurred to me to recross them with her post transfusion sample, see if any of them are incompatible now. If so, we might need to further evaluate that donor's E status (like Dave was talking about earlier- maybe some weird antigen that the monoclonal isn't picking up).

Hmmmmm......

[Packer Banker]

Your platelet theory is certainly a possibility. I don't remember the allowable RBCs in an apheresis unit- I think it's 5ml, but most fall below 2ml. It is large enough that our policy is to give Rh- women of child-bearing age Rh- platelets to avoid her forming an Anti-D. I assume all institutions have this policy as well? (Except in emergency, physician approved circumstances of course) The 478 bed, Level I hospital I worked in had this policy as well.

Who'd have thought- after all the unxm'd blood- to get an antibody from platelets!

[lauried01]

Well, it seems Dave's initial thought about antigen typing may have been the solution- the ref. lab couldn't get an answer on the eluate (too weak now), but I decided to play a little more. I recrossed the c neg, supposedly E neg units with the POSTTRANSFUSION sample containing the Anti-E- lo and behold, one unit is now INCOMPATIBLE. I retyped that unit AGAIN with the only source of Anti-E monoclonal we have- still types as E neg. Weird....

She must've had the E before, though, for it to just jump up so quickly (possibly a pregnancy exposure).

Sure don't want to see her come back in for a while.....

[NedB]

The antibody you found could be a cE, an antibody which will react with both c and E and would be absorbed by either antigen (ce or CE). And don't forget that most instances of Anti-E are natural - no known stimulus, although I would doubt this is the case given the time table you cited. The reference lab could do the absorption I mentioned to set your mind at ease.

[galvania]

I think you really need to retype the unit with a polyclonal anti-E; the donor might have a variant E not being picked up by the clone

[yolis76]

I have seen this happen a few times with patients... I think sometimes any trigger to the immune system will cause other previously formed antibodies to show up again, even if you gave Ag neg red cells. We currently have a case of a patient with a Hx of Anti-Fya, had a couple Fya neg units given at another facility, came to us a few days later with a positive DAT and Anti-Fya in the eluate.... according to the patient he did not get any other blood, and the facility insists was given Fya neg blood. I am constantly challenged to understand such strange occurrences, to the point that I get exhausted!

Also, in regards to your re-XM of c neg E neg units, the Anti-Sda could have made you XM incmp.

[Mabel Adams]

Interesting that the anti-Fya would be in the eluate when there shouldn't have been any Fya antigens in the patient for the antibody to attach to. . .non-specific adherence of antibody to Fya neg cells??

[Eagle Eye]

Or may be unit typing for Fya may have beed false negative. Once we had problem with Immucor reagent where we got false negative results.