Cell-free nucleic acids (CFNAs) are often present in plasma. A new study tested whether CFNAs are also present and active in red blood cell (RBC) units, fresh frozen plasma units, and platelet concentrates. Using a nanochip bioanalyzer, double-stranded DNA fragments were found in RBC units, platelet concentrates, and fresh frozen plasma units. Significant concentrations of RNA were not observed in any of the blood products. Although CFNA concentrations significantly varied between the same blood component units, there was no effect of storage time on CFNA concentrations. In addition, the study examined microarray data collected after CFNAs (from RBCS, plasma, and platelets) were cultured with macrophages. There was an increase in the expression of over 900 genes, including chemoattractant CXCL-8 (IL-8) and other genes involved in innate immunity and inflammation. Further studies are necessary to determine if CFNAs are detectable and/or biologically active after transfusion.
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These data can give at least in part biological plausibility to recent findings by Caraam-Deelder and coll published in JAMA in 2017, that show an increased mortality in males over 50 transfused with RBC by ever pregnant women. Fetal Free DNA is likely to persist after delivery in maternal plasma; thus we can hypothesise that multiple inflammatory triggers – driven by the mothers and one or more fetuses could lead to an increased”inflammation” and in turn to an activation of coagulation with an increased rate of mortality.