Hyperhemolysis syndrome in a patient without a hemoglobinopathy, unresponsive to treatment with eculizumab

BackgroundHyperhemolysis is a serious transfusion reaction, most often described in patients with hemoglobinopathies. Hyperhemolysis is characterized by the destruction of host red blood cells (RBCs), in addition to donor RBCs, via an unknown mechanism. Study Design and MethodsWe present the case of a 58-year-old woman with treated human immunodeficiency virus and a normal hemoglobin (Hb) electrophoresis who developed hyperhemolysis in the setting of a delayed hemolytic transfusion reaction (DHTR). ResultsThe patient was ABO group B and had a previously identified anti-Fy(b) alloantibody. After transfusion of Fy(b)- RBCs, she developed a DHTR and was found to have anti-E, anti-C-w, anti-s, and an additional antibody to an unrecognized high-frequency RBC alloantigen. Subsequent transfusion of ABO-compatible RBCs that were negative for Fy(b), E, C-w, and s antigens resulted in immediate intravascular hemolysis. In the absence of bleeding, her hematocrit (Hct) decreased to 10.2%. An extensive serologic evaluation failed to identify the specificity of the high-frequency antibody. Severe hemolytic reactions also occurred despite pretransfusion conditioning with eculizumab. The Hct and clinical symptoms slowly improved after the cessation of transfusions and treatment with erythropoietin and steroids. This case demonstrates several noteworthy features including hyperhemolysis in a patient without a Hb disorder, the development of an antibody to an unknown RBC antigen, and the failure of eculizumab to prevent intravascular hemolysis after transfusion. ConclusionHyperhemolysis is not restricted to patients with hemoglobinopathies. Whether eculizumab offers any benefit in the hyperhemolysis syndrome or in the prevention of intravascular hemolysis due to RBC alloantibodies remains uncertain.