Blood Transfusion Research Today is a free monthly online journal that collates and summarizes the latest research about Blood Transfusion, including details on blood donation, blood types, leukemia. | ||||||||
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Inflammation enhances consumption and presentation of transfused RBC antigens by dendritic cells.Hendrickson JE, Chadwick TE, Roback JD, Hillyer CD, Zimring JC Department of Pediatric Hematology/Oncology, Emory University School of Medicine, Children's Healthcare of Atlanta, AFLAC Cancer Center and Blood Disorders Service, Atlanta, GA 30322, USA. Factors regulating which patients become alloimmunized to red blood cell (RBC) antigens are poorly understood. Using a murine model of transfusion, we recently reported that viral-like inflammation with polyinosinic polycytidylic acid [poly (I:C)] significantly enhances RBC alloimmunization. Herein, we tested the hypothesis that poly (I:C) exerts this effect, at least in part, at the level of antigen-presenting cells (APCs). Using a novel in vivo method, we report that in the noninflamed state, most transfused RBCs were consumed by splenic macrophages, with only trace consumption by splenic dendritic cells (DCs). To a lesser extent, RBCs were also consumed by APCs in the liver. However, unlike soluble antigens, no RBCs were consumed by APCs in the lymph nodes. Inflammation with poly (I:C) induced significant consumption of transfused RBCs by splenic DCs, with a concomitant increase in costimulatory molecule expression. Moreover, this resulted in increased proliferation of CD4(+) T cells specific for the mHEL RBC alloantigen. Finally, splenectomy abrogated the enhancing effects of poly (I:C) on RBC alloimmunization. Together, these data provide additional insight into the nature of transfused RBCs as an immunogen and provide a mechanism by which viral-like inflammation enhances alloimmunization to transfused RBCs. Published 20 September 2007 in Blood, 110(7): 2736-43.
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