TRALI

PREVENTION: Now what? All AABB-accredited facilities must have a plan in place to attempt to reduce the incidence of TRALI.

In order to understand how to prevent recurrence of TRALI, you need to have a good handle on the main mechanisms postulated for TRALI (if you don't remember them, click the "Mechanism" link in the box at the bottom of this page and review, then come on back and we'll talk some more!).

If TRALI is shown to be caused by a transfused antibody, we can sometimes identify the donor who carries that antibody. If that is the case, then that particular donor may very well cause another patient to have a similar reaction, so it is best for that patient not to donate blood in the future, or to be limited to products with minimal residual plasma, like washed red cells (this recommendation is from an August 11, 2005 AABB bulletin on TRALI).

As straightforward as the above may sound, it is not necessarily that easy to implicate a particular donor as the cause of antibody-related TRALI. Formal workups for TRALI are difficult and time-consuming, and are decidedly NOT "stat" tests! Demonstration and identification of an antibody in the donor, and a demonstrated incompatibility with the recipient's HLA and/or neutrophil type require time and patience. Such a workup is not something that most community hospital labs can do, and most TRALI workups require referral to a more advanced laboratory.

HLA antibodies are most common in two groups: Patients who have had multiple transfusions and multiparous females. As a result, in the United Kingdom, multiparous females have been banned from donating plasma-containing products to try to reduce the risk of TRALI (early data shows apparent success in reducing TRALI deaths, by the way). In the United States, the majority of blood centers and hospitals have made it their policy to collect as many plasma-based products (FFP, apheresis platelets) from male donors. Many centers have undertaken specific screening of multiparous females to screen for offending antibodies that may cause TRALI, as well. Early data suggests that this strategy may be bearing fruit in the US, as well.

So, what is the issue, really? For red cells, female donors (even multiparous ones) are not a problem. Our problem arises in apheresis platelet donors and donors whose plasma results in plasma for transfusion (whole blood donors and apheresis donors alike). Plasma-rich products containing an anti-HLA or anti-neutrophil antibody are more likely to cause a problem for our recipients. As a result, blood centers are focusing on how to make these donors safer. Simply saying that all plasma and platelet donors must be male is not realistic (especially for platelets). This is why many centers have begun screening their multiparous female donors for antibodies, and allowing them to donate plasma-rich products if they screen negatively.

If the episode of TRALI has been caused by a "two-event" model (as originally described, without a transfused antibody), there really isn't anything specific that Blood Bankers can do be sure of prevention of future episodes, other than to avoid transfusion as much as possible! Logically, one might think that giving fresher blood products (that haven't had a chance to accumulate as much of the lipid priming agents) might work, but the implications on management of our inventory have disastrous potential (i.e., if everyone wants the freshest possible blood, we are going to have a problem very quickly!). Washing the blood products that a patient at risk for TRALI receives has also been reported to be effective.

OK, that's it for this section! Click to go back to Transfusion Reaction Types and check out another transfusion reaction.

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