Immunologic profiles of red blood cells using in vitro models of transfusion

Abstract

Background Transfusion of packed red blood cells (RBCs) produces a myriad of immunologic derangements, from suppressive to stimulatory. Proliferation of human T cells is suppressed in vitro after exposure to processed red blood cells (PRBCs). We hypothesized that this effect would be mitigated by using fresh RBCs. We also hypothesized that this suppressive effect was a generalized effect on lymphocyte proliferation and would be observed in both CD4+ and CD8+ T-cell subpopulations as well as B cells. Materials and methods We isolated human T cells from donor peripheral blood mononuclear cells and exposed them to either blood bank PRBCs or fresh RBCs from volunteer donors and stimulated them with anti-CD3/anti-CD28. Human B cells were stimulated with lipopolysaccharide and exposed to PRBCs or fresh RBCs. We measured proliferation of B cells by thymidine incorporation assays. We also treated RBCs with citrate-phosphate-dextrose (CPD) at different time points before culture them with stimulated T cells to determine the role of this common RBC storage solution in lymphocyte proliferation. Results In vitro proliferation of CD4+ and CD8+ T cells was suppressed by blood bank RBCs. This suppression is eliminated when fresh RBCs were used. The B cells showed inhibition of proliferation when exposed to similar conditions, which appeared to be consistent over serial dilutions. Fresh RBCs exposed to CPD did not appear suppressive in the first 6 h after exposure. Conclusions T-cell and B-cell proliferation inhibition by blood banked RBCs suggests a generalized effect of RBCs on cellular proliferation. The lack of suppression by fresh RBCs further suggests that something involved in blood banking alters RBC properties such that they attain a suppressive phenotype. One such blood banking component, CPD, does not appear to affect this suppressive phenotype within the first 6 h.

Characterisation of dendritic cell immune profile in models of transfusion

“…These results are similar to a previous study which focused on responses to PC supernatants [168]. [79,80,88,289]. While changes in the overall leukocyte inflammatory response were evident, it is important to consider these results predominantly represent the response of the more abundant leukocyte subsets, such as neutrophils and lymphocytes.…”

“…I found minimal modulation of cytokine responses following exposure to PRBC alone, however, both mDC and BDCA3 + DC responses to polyI:C and LPS were suppressed in the presence of PRBC. Together poor co-stimulation and lack of cytokine and chemokine production may be associated with inadequate T and B lymphocyte responses [79,80,88] and my data suggest PRBC transfusion has the potential to impair downstream lymphocyte responses.…”

“…However, in another study PRBC supernatants increased the number of regulatory T lymphocytes (CD25 + Treg) and reduced the number of T responder lymphocytes (CD25 -) [79]. A more recent study indicates B and T lymphocyte proliferation was suppressed following exposure to leukodepleted PRBC stored for two to three weeks, but not freshly collected leukodepleted RBC [88]. Suppression of T lymphocyte proliferation has also been reported in studies utilising PRBC in a whole blood model [84], and in a cell culture model utilising PRBC supernatants and Jurkat T lymphocytes [80].…”

“…The potential for PRBC to modulate recipients' immune response and impact patient outcomes has been studied using in-vitro [79][80][81][82][83][84][85][86][87][88][89] and in-vivo [90] models. An in-vitro study using a whole blood model reported increased interleukin (IL)-10 production and reduced tumour necrosis factor (TNF)-α production by the overall leukocytes in the culture supernatant following 24 h exposure to either autologous or allogeneic PRBC [81].…”

“…Increased monocyte erythrophagocytosis of stored PRBC has also been reported [283]. Transfusion-related modulation of immune responses are not limited to innate cells, with exposure to PRBC reported to increase CD25 + regulatory T lymphocyte production, reduce the number of responder T lymphocytes [79], and suppress B and T lymphocyte proliferation [80,88]. To date, studies assessing the role of DC in transfusion outcomes are limited.…”