Association between gene expression biomarkers of immunosuppression and blood transfusion in severely injured polytrauma patients.

ABSTRACT

OBJECTIVE: To explore the hypothesis that blood transfusion contributes to an immunosuppressed phenotype in severely injured patients. BACKGROUND: Despite trauma patients using disproportionately large quantities of blood and blood products, the immunomodulatory effects of blood transfusion in this group are inadequately described. METHODS: A total of 112 ventilated polytrauma patients were recruited. Messenger RNA (mRNA) was extracted from PAXGene tubes collected within 2 hours of the trauma, at 24 hours, and at 72 hours. T-helper cell subtype specific cytokines and transcription factors were quantified using real-time polymerase chain reaction. RESULTS: Median injury severity score was 29. Blood transfusion was administered to 27 (24%) patients before the 2-hour sampling point. Transfusion was associated with a greater immediate rise in IL-10 (P = 0.003) and IL-27 (P = 0.04) mRNA levels. Blood products were transfused in 72 (64%) patients within the first 24 hours. There was an association between transfusion at 24 hours and higher IL-10 (P < 0.0001), lower Foxp3 (P = 0.01), GATA3 (P = 0.006), and RORγt (P = 0.05) mRNA levels at 24 hours. There were greater reductions in T-bet (P = 0.03) mRNA levels and lesser increases in TNFα (P = 0.015) and IFNγ (P = 0.035) at 24 hours in those transfused. Multiple regression models confirmed that the transfusion of blood products was independently associated with altered patterns of gene expression. Blood stream infections occur in 15 (20.8%) of those transfused in the first 24 hours, compared with 1 patient (2.5%) not transfused (OR = 10.3 [1.3-81], P = 0.008). CONCLUSIONS: The primarily immunosuppressive inflammatory response to polytrauma may be exacerbated by the transfusion of blood products. Furthermore, transfusion was associated with an increased susceptibility to nosocomial infections.