Transfusion Reaction - Positive DAT, Negative Eluate

[SusieQ132]

Sorry for the novel!  I have an odd case that I wanted some input on.  

Patient History:  66 year old female with CMML.  A Pos, with a negative antibody screen, no history of clinically significant antibodies.  Has HLA antibodies that have never been detected in our IgG antibody screen testing, but cause her to be refractory to random platelet transfusions.  Has been getting HLA-matched platelets.  She has received 9 RBCs and 24 apheresis PLTs over the month of September. 

Transfusion Reaction:  The patient received 1 O Pos HLA-matched apheresis platelet (Anti-A titer <1:200) on 8/29/16 at 1100, and 1 electronically compatible A Pos PCLR right after the platelet was done infusing.  After the RBC infusion, the patient developed chills/rigors, flushing, and felt tired and "out of it" according to the RN.  Her temperature had increased >2 degrees F, so a transfusion reaction investigation was initiated.

BB Testing: 

• Clerical Check OK
• Gram stain on both the RBC and PLT were negative.
• Cultures from both are still pending.
• Post-Rxn Sample:
  • ABO/Rh = A Pos
  • Poly (IgG/C3) DAT = 1+ Positive
  • Mono IgG DAT = 2+ Positive
  • Mono C3 DAT = 1+ Positive
  • Aby Screen = Negative
  • Plasma color = slightly darker than Pre-Rxn sample, but not visably hemolyzed
• Pre-Rxn Sample:
  • Poly (IgG/C3) DAT = Negative 
  • Aby Screen = Negative
• Gel/AHG XM of transfused RBC with Pre- and Post-Rxn samples = Negative/Compatible
• RBC unit DAT = Negative

So, we obviously decided to perform an eluate on the post-reaction sample.  The eluate was tested against screen cells, A1 cells, B cells, and panel cells, and showed no reactivity.  Questioning the original eluate, we performed an eluate on a new post-reaction sample the next morning (8/30), and got the same results. 

We decided to try running both eluates against the transfused RBC and the patient's own cells from the pre-reaction (DAT negative) sample.  The eluate did not react with the transfused RBC, but reacted 1+ with the patient's Pre-Rxn sample. 

How the heck do I explain this!?

~Susan

[Yanxia]

I guess the antibodies come from the donors. And the antobodies are against low infrequency antigens on the recipient's red cells, so" the eluate did not react with the transfused RBC...and the panel cells..."

[galvania]

I would check again now and see if there's any change.  Also, if you can, test the platelet donor for antibodies against low frequency antigens, and maybe re-test his anti-A titre.  Maybe the red cell donor was an A2 and the patient is an A1 so the anti-A would hit the patient cells more than the donor cells.  And how did you do the eluate?  Maybe not the best method for detecting anti-A???

[SusieQ132]

New information: 

• The patient's post-RXN plasma reacts 1+ with the patient's pre-RXN red cells.  (So whatever it is, it is in the plasma, too!)
• We performed an antibody screen on the plasma from the platelet unit, and that was negative. 
• We have ruled out Anti-Js^a, -Kp^a, -V, -C^w, and -Lu^a in the eluate.

The eluate was performed using the Elu-Kit (acid elution).  I know this isn't the best for picking up Anti-A, but we have picked it up using this kit in the past, so it was surprising not to see it this time. 

At this point, the patient doesn't show any signs of hemolysis, and the significance of this positive DAT is unclear.  We are going to crossmatch at AHG for future RBC needs as a precaution, but we aren't going to pursue it further.

 

My wild theory: 

The patient had received Zosyn (Tazobactam-Piperacillin) and Vancomycin, which have both been reported to cause drug-induced hemolytic anemia.  These were given a few weeks prior to the transfusion reaction, and theoretically, the patient could have formed Anti-Piperacillin (or another drug antibody) that only reacts in the presence of the drug.  Then, the platelet or RBC donor took the medication, and it was passively administered to the patient with the blood component.  Then, the drug was introduced back into the patient's system and caused a positive DAT.  Or maybe the donor has Anti-Piperacillin (or another drug antibody).     

Not very likely.  But you never know!

[mcgouc]

One day I was training a new tech at the end of the day. They called a reaction & I was going through the process saying how much easier it is now than when I started Blood Banking & the work ups didn't take much time. Positive post DAT. Negative elate. I decided to test some low incidence positive cells & there was an anti-Diego a in eluate (and in pretransfusion plasma when we tested that with those cells).  I just told myself to "never say never" in Blood Banking.