Hello and welcome to Transfusion News. Today we will be discussing recent insights into TRALI or transfusion-related acute lung injury. TRALI is a clinical condition of respiratory distress after transfusion, and the leading cause of transfusion-related fatalities.
Current mitigation strategies have helped to decrease the incidence of TRALI for plasma transfusions. However, platelet and red blood cell transfusions are now the leading blood products associated with TRALI. More than one mechanism may trigger TRALI. One of the major causes of TRALI is donor antibodies to white blood cells, such as to HLA. Class I in humans, which triggers the patient’s innate immune response leading to lung injury.
Dr. Semple recently published a study in BLOOD that provides further insight into the pathophysiology. Monocytes, not neutrophils, as previously thought, are necessary for the initial event.
Here is Dr. Semple:
“The antibody, after it’s infused, very quickly will attach itself to monocytes so that they secrete molecules that are called chemokines. These chemokines will attack and activate neutrophils. We found that this was a critical event. If you got rid of either monocytes or if you blocked the chemokine production or binding to its receptor, in fact, you could alleviate all the TRALI symptoms.”
In a separate study, Dr. Silliman shows that a modified leukoreduction filter for red blood cell products mitigated TRALI in a mouse model. The filter primarily removes IgG antibodies such as those that have been implicated in causing TRALI, and also decreases bioactive lipids.
Dr. Silliman elaborates:
“The filter works. We now have to take it into clinical trials—phase I—make sure it’s safe.”
Dr. Shaz of the New York Blood Center states:
“I think the filter is feasible. To date we’ve really focused on kind of blunt instruments for TRALI mitigation by eliminating donors rather than being more focused. So this filter allows us to address the important things, and we don’t need these factors in the red cells so we might as well take them out.”
With advanced methods to decrease factors in the blood supply that trigger TRALI and a better understanding of the mechanism, we should be able to continue to reduce TRALI-related fatalities.
We’ll be back with another edition of Transfusion News on July 15. Thanks for joining us.
1. McKenzie CG, Kim M, Singh TK, Milev Y, Freedman J, Semple JW. Peripheral blood monocyte-derived chemokine blockade prevents murine transfusion-related acute lung injury (TRALI). Blood 2014;123: 3496-503.
3. Silliman CC, Kelher MR, Khan SY, LaSarre M, West FB, Land KJ, Mish B, Ceriano L, Sowemimo-Coker S. Experimental prestorage filtration removes antibodies and decreases lipids in RBC supernatants mitigating TRALI in vivo. Blood 2014;123: 3488-95.