title: Blood transfusions downregulate hematopoiesis and subsequently downregulate the immune response.
abstract: BACKGROUND
  Blood transfusions are associated with numerous clinical phenomena attributable to reduced posttransfusion immunocompetency. The exact mechanism by which blood transfusions induce a state of reduced immune responsiveness remains unclear.
  
  
  METHODS
  The effect of a large-volume blood transfusion on the frequency and responsiveness of immune cells in lymphoid compartments was examined in normovolemic rats. The effects of syngeneic and allogeneic blood transfusions were compared.
  
  
  RESULTS
  The results in normovolemic rats were compared to those in nontransfused and saline-infused animals. In the normovolemic rats, there was a significant decrease in cells of erythroid lineage in bone marrow, with a slight increase in the percentage of cells in the bone marrow myeloid and lymphoid lineages; a significant increase in the percentage of the OX7+ Thy1+ cell population in bone marrow cells (stem cells are contained in this population) and blood cells; a decrease in the bone marrow OX6+ cell population (HLA class II-positive cells); a decrease in the responsiveness of blood, spleen, lymph node, and bone marrow cell populations to mitogens; and a downregulating effect of both syngeneic and allogeneic blood transfusions on hematopoiesis and cell responsiveness.
  
  
  CONCLUSIONS
  Massive whole blood transfusion, either syngeneic or allogeneic, constitutes a strong downregulating signal for hematopoiesis, affecting the erythroid, myeloid, and lymphoid cell lineages. It leads also to an attenuation of the responsiveness of hematopoietic tissues to mitogenic stimuli.
authors.affiliation: Surgical Research and Transplantation Department, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: I
authors.initials: I
authors.lastname: Grzelak
authors.forename: M
authors.initials: M
authors.lastname: Zaleska
authors.forename: W L
authors.initials: WL
authors.lastname: Olszewski
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis; D001803:Blood Transfusion; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology; D002452:Cell Count; D003208:Concanavalin A / Q000494:pharmacology; D015536:Down-Regulation; D006410:Hematopoiesis / Q000502:physiology*; D007111:Immunity, Cellular / Q000502:physiology*; D007958:Leukocyte Count; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008214:Lymphocytes / Q000187:drug effects; D010835:Phytohemagglutinins / Q000494:pharmacology; D011043:Pokeweed Mitogens / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000166:cytology / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D010835:Phytohemagglutinins; D011043:Pokeweed Mitogens; D003208:Concanavalin A