Page 1 of 1: Allergy-Transfusion

goldenhand · Credits: 19368 My Scrapbook

A 58-year-old man with severe ischemic cardiomyopathy is being evaluated for an expedited heart transplant. He is currently in the cardiac care unit, where he is maintained on inotropic support as a bridge to transplant. Among his numerous medical problems, he suffers from an anemia of chronic disease and his hematocrit has been drifting progressively lower. Today his hematocrit is 29%, and the decision is made to transfuse the patient carefully with 2 U of packed red blood cells. There is some concern about HLA alloimmunization because the patient has received multiple transfusions in the past and may well need more transfusions before receiving a donor heart. It is felt that the patient risks developing antibodies to antigens on donated tissue. In order to reduce this risk, the blood should be ordered as which of the following?

A. Frozen deglycerolized red blood cells

B. Irradiated red blood cells

C. Leukoreduced red blood cells

D. No modifications, packed red blood cells

E. Washed red blood cells

botak 1 · Credits: 12608 My Scrapbook

E. Washed red blood cells

goldenhand · Credits: 19368 My Scrapbook

The correct answer is C. Most allosensitization occurs from leukocyte antigens. Indeed, most febrile transfusion reactions are related to immune-mediated reactions associated with transfused white blood cells, not red blood cells. In addition to reducing the risk of allosensitization, leukoreduction can significantly reduce the transmission of cytomegalovirus, which resides in white blood cells and can cause serious infections in immunosuppressed hosts.
Frozen deglycerolized cells (choice A) are rarely used. This process is used in IgA-deficient patients for whom a donor cannot be found, because this process will remove more antigens than washing alone. This process is also used to store certain rare blood types.
Irradiated red blood cells (choice B) are often used in neutropenic patients. Irradiation will kill most organisms that are present in blood.
If allosensitization were not a concern, then no modifications (choice D) would be necessary. If the patient just needed blood and were not a transplant candidate, then transfusion with packed red blood cells would be appropriate.
Washed red blood cells (choice E) have the small amount of residual plasma removed immediately before transfusion. Washed cells are used for patients with severe or recurrent allergic reactions, in patients with IgA deficiency (when IgA-deficient donors or frozen deglycerolized red cells are not available), and in patients with complement-dependent autoimmune hemolytic anemia to prevent complement infusion.

concorde · Credits: 580 My Scrapbook

C. Leukoreduced red blood cells

Ron09 · Credits: 6242 My Scrapbook

E. Washed red blood cells

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