N Mullis

This certainly sounds most consistent with an autoantibody. Here's a few questions first: 1) Were you able to obtain DAT negative autologous cells (by EDTA-Glycine Acid or Chloroquine diphosphate treatment), and if so, did you test them with the patient's plasma and eluate to confirm that auto-reactivity is present? 2) Were the adsorbing cells used for the PeG adsorptions also papain-treated? It's possible that a component of the antibody(ies) that you are dealing with is enzyme-sensitive and that is why adsorption is not successful. You might want to test the adsorbed plasma with the adsorbing cells (papain-treated and untreated) to see if the adsorbed plasma continues to be reactive with those cells. If it is non-reactive with the papain-treated cells but reactive with the untreated cells, you could continue the adsorptions with untreated cells (with added caution since other specificities may be adsorbed out, depending on the phenotype of the adsorbing cells). 3) Are the cells you have tested with the adsorbed plasma phenotypically similar? You may want to try several different phen sim cells, since many of these cells also have low incidence antigens on them. Or you can also test the DAT negative autologous cells (previously mentioned) with the adsorbed plasma to see if autoantibody is still present. Best of luck with sorting this out!

Excuse me for jumping in, but there is far, far too little information provided here to leap into the assumption that an autoantibody is present in the plasma. What was the transfusion history? The original post seems to be asking the question "does a positive DAT invalidate the panel results?" and the answer to that question is "No". If you are getting clear positive and negative results in the plasma testing, I would assume that the antibody(ies) detected are alloimmune (unless the patient's cells type positive for the associated antigens, then that's a different question with a long answer). The DAT could be positive due to things such as recent transfusion (delayed transfusion reaction), certain medications, a developing autoimmune process... I would suggest evaluating the DAT by checking the medical history for transfusions and medications before going the autoantibody route. Also at least an initial elution should be performed before making the interpretation of autoantibody to confirm that a panagglutinin IS present in the eluate. Some drug-induced antibodies are not distinguishable from warm-autoantibodies except by the eluate results (which are non-reactive in routine testing in the case of drug-induced hemolytic anemia).

You know, I hate to be the bearer of bad news but the manufacturer's instructions for gel cards do NOT support recentrifugation of the cards as a valid test method. There may be other reasons that results are not reproducible (e.g. fibrin, weak antibodies, variations in samples collected), but centrifuging the card again is not the way to resolve the problem! I hope no one is using this method to interpret patient test results! From the insert: 1. False positive or false negative test results can occur from bacterial or chemical contamination of test materials, inadequate incubation time or temperature, improper centrifugation, improper storage of materials, or omission of test samples. 2. Proper centrifuge calibration is particularly important to the performance of the MTS Anti-IgG Card. TheMTS Centrifuge has been exclusively designed to provide the correct time, speed and angle. and For best results, it is recommended that following centrifugation, results should be read immediately. If tests are not read immediately, results may be affected by the drying out of the gel; hemolysis of the red cell and slanting of the reaction patterns due to storage in a non upright position.

More information please! Do you know her ethnic background? What is her blood type? Were there any reactions at immediate spin? How strong is the reactivity? Since the enzyme-treated cells only reacted when tested with PEG, does that mean this antibody is non-reactive without enhancement media? What does it look like if tested by LISS 37/IAT, Gel or with no enhancement? Did you try to titrate it? Could underlying antibodies be interfering with your results? Will it adsorb and elute?

Hey Karen, I'm assuming that you're talking about -65C freezers for storage of red cell units vs liquid nitrogen freezers for rare reagent cells? We currently are moving our inventory from chest freezers to upright freezers. It was impossible to find anything in the chest freezers, and looking for units involving moving everything around on the top layer in order to see what was on the bottom layer. Needless to say, this wasn't always carefully done and resulted in broken units. The upright freezers are easier to organize, and we are posting the contents (by section) on the outside of the freezer to eliminate holding the door open. The worst thing about upright freezers is the cold "drops out" when the door is open and alarms go off quickly. I hope your new lab is working out for you! Good luck!

"Is it possible for an R1wR1 individual produce Anti-c(little c), Anti-Cw in combination with Anti-E and Anti-Bg." In response to this question, are you certain that the patient has the R1wR1 phenotype? This infers, to me, that the patient was typed positive for the Cw antigen. In that case, it would be pretty unlikely that the person produced anti-Cw. Anti-c and -E are pretty common antibodies in R1R1 or R1wR1 individuals. "Anti-Bg" is a little vague - since "Bg" is not a specific antigen. Perhaps they just meant to convey the presence of antibodies to HLA antigens....

Claudia, are you planning to do auto- or allogeneic adsorptions, or both? We have been doing PEG adsorptions for several years, and our experience has been more efficient removal of the autoantibody regardless of the strength of reactivity. I assume you have read about the downside of this procedure (loss of alloantibody reactivity in some cases). We primarily use allogeneic adsorption with papain-treated cells, and most autoautoantibody reactivity is sufficiently removed after 1-2 adsorptions. Let me know if you need more information or references!

Hi Claudia! I think it's interesting that your antibody doesn't react with cells that are positive for the low incidence antigens in the Kell system. I have to wonder if it is Kell system related....I would try testing some DTT-treated or EGA-treated cells. Since the reactivity is so weak, I wonder if the antibody is directed toward a high-incidence antigen in the Kell system and the presence of K, Jsa or Kpa affects the antigen expression of the HIA. As an aside, I think PEG is a great reagent and much of the "scratchy junky" reactions people are describing actually turn out to be identifiable in a Reference Lab setting. We see no more "extraneous" reactions in PEG than we do in any other media.