American Board of Internal Medicine (ABIM) Certification Practice Exam

In cases of platelet transfusion refractoriness due to alloimmunization, what should patients receive?

1. Regular platelets

2. HLA-matched platelets

3. Whole blood transfusions

4. Cryopreserved platelets

The correct answer is: HLA-matched platelets

In cases of platelet transfusion refractoriness caused by alloimmunization, patients should receive HLA-matched platelets. Alloimmunization occurs when a patient's immune system develops antibodies against transfused platelets, often due to previous transfusions or pregnancies. These antibodies target specific human leukocyte antigen (HLA) antigens on the transfused platelets, leading to a poor response to standard platelet transfusions. HLA-matched platelets are derived from donors who share the same HLA characteristics as the recipient. By using these matched platelets, the risk of the recipient's immune system recognizing the transfused platelets as foreign is significantly reduced. This improves the likelihood of effective transfusion and helps to stabilize the patient's platelet counts. Other options, such as regular platelets, would not address the underlying problem of alloimmunization and could lead to continued refractoriness. Whole blood transfusions are not a practical solution for addressing platelet specific issues and would expose patients to risks associated with red blood cells and plasma. Cryopreserved platelets, while useful in certain scenarios, do not directly resolve the refractoriness caused by HLA antibodies. Therefore, HLA-matched platelets are the best approach for managing this specific