SHM Converge Scientific Abstract ePoster Gallery-Transfusion Challenges Due to a Rare Kell Autoantibody

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A 69-year-old man with prostate cancer in remission and angioimmunoblastic T-cell lymphoma on chemotherapy presented after a fall and was found to have fever and severe pancytopenia, including marked anemia (Hgb 6.6) and thrombocytopenia. Workup showed a hypoproliferative anemia without evidence of hemolysis, negative infectious studies, and prior bone marrow findings consistent with lymphoma progression. His cytopenias were attributed to worsening AITL, compounded by chemotherapy.<br /><br />Although his clinical picture did not suggest autoimmune hemolytic anemia, his direct Coombs test was positive for warm IgG autoantibodies. More importantly, his indirect Coombs test identified an anti-Kpb antibody. Anti-Kpb is a very rare but clinically significant Kell alloantibody that can cause hemolytic transfusion reactions. Because compatible Kp(b-) red blood cell units were uncommon, blood had to be specially sourced through the Red Cross, delaying packed RBC transfusion by several days.<br /><br />The case highlights key transfusion principles. A positive direct Coombs test does not necessarily indicate clinically meaningful hemolysis; many patients with warm autoantibodies tolerate transfusion safely when blood is urgently needed, and transfusion should generally not be delayed solely for this reason. In contrast, a positive indirect Coombs test may reveal alloantibodies that require transfusion medicine review to prevent hemolytic reactions and to locate antigen-negative donor blood.

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Caroline Coleman

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Author List Brett Montelaro, Caroline Chivily, Caroline Coleman, Dustin T. Smith, Eric Caliendo, Harshita Jain, Vidya Viswanathan

Category Clinical Vignettes

Concept Direct Antiglobulin Test

Concept RBC Alloantibody

Concept Warm Autoantibody

Concept Kell Antibody

Concept Anti-Kpb

Distinguished Non-Finalist

Presenter Organization Emory University School of Medicine (Atlanta VA)

Presenting Author Caroline Coleman

Track Adult

Keywords

angioimmunoblastic T-cell lymphoma

pancytopenia

anemia

thrombocytopenia

direct Coombs test

indirect Coombs test

anti-Kpb antibody

Kell alloantibody

transfusion reaction

antigen-negative blood

Direct Antiglobulin Test

RBC Alloantibody

Warm Autoantibody

Kell Antibody

Anti-Kpb