I. Grzelak et al., BLOOD-TRANSFUSIONS DOWN-REGULATE HEMATOPOIESIS AND SUBSEQUENTLY DOWN-REGULATE THE IMMUNE-RESPONSE, Transfusion, 38(11-12), 1998, pp. 1104-1114
BACKGROUND: Blood transfusions are associated with numerous clinical p
henomena attributable to reduced posttransfusion immunocompetency. The
exact mechanism by which blood transfusions induce a state of reduced
immune responsiveness remains unclear. STUDY DESIGN AND METHODS: The
effect of a large-volume blood transfusion on the frequency and respon
siveness of immune cells in lymphoid compartments was examined in norm
ovolemic rats. The effects of syngeneic and allogeneic blood transfusi
ons were compared. RESULTS: The results in normovolemic rats were comp
ared to those in nontransfused and saline-infused animals. In the norm
ovolemic rats, there was a significant decrease in cells of erythroid
lineage in bone marrow, with a slight increase in the percentage of ce
lls in the bone marrow myeloid and lymphoid lineages; a significant in
crease in the percentage of the OX7+ Thy1+ cell population in bone mar
row cells (stem cells are contained in this population) and blood cell
s; a decrease in the bone marrow OX6+ cell population (HLA class II-po
sitive cells); a decrease in the responsiveness of blood, spleen, lymp
h node, and bone marrow cell populations to mitogens; and a downregula
ting effect of both syngeneic and allogeneic blood transfusions on hem
atopoiesis and cell responsiveness. CONCLUSION: Massive whole blood tr
ansfusion, either syngeneic or allogeneic, constitutes a strong downre
gulating signal for hematopoiesis, affecting the erythroid, myeloid, a
nd lymphoid cell lineages. It leads also to an attenuation of the resp
onsiveness of hematopoietic tissues to mitogenic stimuli.