Department of Pathology and Laboratory Medicine, University of Texas Health, San Antonio.
Department of Pathology, Texas Tech University, The Hospitals of Providence, El Paso.
Am J Clin Pathol. 2021 Jan 4;155(1):117-123. doi: 10.1093/ajcp/aqaa117.
RBC alloantibodies can lead to ABO grouping discrepancies unrelated to A or B antigens or antibodies posing challenges in the blood bank testing. Routine blood bank testing and flow cytometry were used to immunophenotype reagent cells and elucidate the cause of ABO discrepancies in two patients.
ABO discrepancy was identified in two patients after transfusion with several units of RBCs. For both patients, the pretransfusion type and screen demonstrated blood group A. Eight and 16 days later, both patients showed an apparent antibody to reagent group A cells, which prompted additional study with patients' samples and flow cytometric testing of commercial reagent cells.
In both patients' specimens, posttransfusion evaluation demonstrated an emerging antibody to the Kell antigen (K). The RBCs of both patients typed negative for K, and both were transfused with K-positive RBCs. Flow cytometric analysis of reagent RBCs demonstrated that five of seven lot numbers were positive for K.
Emerging anti-K antibody led to agglutination of the K-positive reagent A1 cells, highlighting the importance of considering RBC alloantibodies and the composition of reagent cells when interpreting cases with an apparent ABO grouping discrepancy.
红细胞（RBC）同种抗体可导致与 A 或 B 抗原无关的 ABO 定型不符，或抗体在血库检测中造成挑战。本研究采用常规血库检测和流式细胞术对试剂细胞进行免疫表型分析，并阐明了两名患者 ABO 定型不符的原因。
两名患者在输注数单位 RBC 后出现 ABO 定型不符。两名患者的输血前血型和筛选均显示为 A 型。8 天和 16 天后，两名患者均出现明显针对试剂 A 细胞的抗体，这促使我们对患者样本进行进一步研究，并对商业试剂细胞进行流式细胞术检测。
在两名患者的标本中，输血后评估显示出现针对 Kell 抗原（K）的抗体。两名患者的 RBC 均为 K 阴性，且均输注了 K 阳性 RBC。对试剂 RBC 的流式细胞术分析显示，7 个批号中有 5 个为 K 阳性。
新出现的抗-K 抗体导致 K 阳性试剂 A1 细胞发生凝集，这突出表明在解释明显的 ABO 定型不符时，需要考虑 RBC 同种抗体和试剂细胞的组成。
