Screening for new red blood cell alloantibodies after transfusion in patients with sickle cell disease

Abstract

Background Patients with sickle cell disease (SCD) are frequent recipients of red blood cell (RBC) transfusions and are at risk for RBC alloimmunization. RBC alloimmunization is diagnosed by identifying RBC alloantibodies as part of pre‐transfusion testing, but this testing fails to detect alloantibodies that have evanesced. It may be beneficial to screen for new RBC alloantibody development after transfusion before possible antibody evanescence. Study Design and Methods Our institution started a new initiative for episodically transfused patients with SCD to obtain at least one antibody screen 2–6 months after transfusion as part of their clinical care. A database was created to prospectively track all transfused patients for 1 year and their post‐transfusion antibody screen results. Patients received prophylactically CEK‐matched RBC units. Results During the study year, 138 patients with SCD received a total of 242 RBC transfusions. Patients with a history of an RBC alloantibody (n = 13, 9.4%) had previously received more RBC units than non alloimmunized patients (median 11 vs. 2 RBC units, p = .0002). A total of 337 post‐transfusion antibody screens were obtained in 127 patients (92.0%) with 110 patients (79.7%) having at least one antibody screen 2–6 months post‐transfusion. With this prospective testing, two new RBC alloantibodies (anti‐C and ‐M) were identified in two patients. Conclusion It is feasible to test for new RBC alloantibody development in most episodically transfused patients with SCD as part of their routine care. The yield of this screening appears low with CEK matching, but it could still provide important information for individual patients.

Preventing antibody positive delayed hemolytic transfusion reactions in sickle cell disease: Lessons learned from a case

“…Stack et al estimated that only about 30% of new RBC alloantibodies are detected clinically through current antibody screening practices 25 . Among paediatric patients with SCD, we found that historically fewer than 18% of patients had an antibody screen obtained 2–6 months after transfusion 26 . While not generally standard of care, it has been proposed that all transfused patients should have a follow‐up antibody screen after a RBC transfusion 27 .…”

“…27 At our institution we recently showed that such screening is feasible, but it appears to be low yield in terms of detecting new alloantibodies in patients with SCD transfused C/E/K matched RBCs. 26 Even if this patient's anti-E alloimmunization had been previously diagnosed at his primary institution, this information would not have been documented at our hospital. Obtaining complete blood bank records is difficult given the lack of a national transfusion database.…”

“…25 Among paediatric patients with SCD, we found that historically fewer than 18% of patients had an antibody screen obtained 2-6 months after transfusion. 26 While not generally standard of care, it has been proposed that all transfused patients should have a follow-up antibody screen after a RBC transfusion. 27 At our institution we recently showed that such screening is feasible, but it appears to be low yield in terms of detecting new alloantibodies in patients with SCD transfused C/E/K matched RBCs.…”

Unmasking delayed hemolytic transfusion reactions in patients with sickle‐cell disease: Challenges and opportunities for improvement

“…This could include routine repeat type and screen, DAT, hemoglobin studies and CBCs at the time of presentation for any SCD complications or for routine evaluation of alloimmunization within a month of transfusion, even in the absence of symptoms. One study showed minimal benefit to routine screening 2–6 months post‐transfusion when the patients were CEK‐matched 38 . However, it is possible that antibodies have evanesced by that time frame.…”

“…One study showed minimal benefit to routine screening 2-6 months post-transfusion when the patients were CEK-matched. 38 However, it is possible that antibodies have evanesced by that time frame. Therefore, we recommend routine, standard of care testing for alloantibodies within 1 month of transfusion.…”