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Coronary artery bypass grafting (CABG) triggers a systemic inflammatory response that may contribute to adverse outcomes. Dendritic cells (DC) and monocytes are immunoregulatory cells potentially affected by CABG, contributing to an altered immune state. This study investigated changes in DC and monocyte responses in CABG patients at 5 time-points: admission, peri-operative, ICU, day 3 and day 5. Whole blood from 49 CABG patients was used in an ex vivo whole blood culture model to prospectively assess DC and monocyte responses. Lipopolysaccharide (LPS) was added in parallel to model responses to an infectious complication. Co-stimulatory and adhesion molecule expression and intracellular mediator production was measured by flow cytometry. CABG modulated monocyte and DC responses. In addition, DC and monocytes were immunoparalysed, evidenced by failure of co-stimulatory and adhesion molecules (eg HLA-DR), and intracellular mediators (eg IL-6) to respond to LPS stimulation. DC and monocyte modulation was associated with prolonged ICU length of stay and post-operative atrial fibrillation. DC and monocyte cytokine production did not recover by day 5 post-surgery. This study provides evidence that CABG modulates DC and monocyte responses. Using an ex vivo model to assess immune competency of CABG patients may help identify biomarkers to predict adverse outcomes. K E Y W O R D Scardiac surgery, coronary artery bypass, Dendritic cells, immune modulation, immunoparalysis, monocytes

Dengue viruses (DENV 1–4) are a risk to transfusion safety, with several transfusion-transmitted (TT) cases reported globally. DENV 1–4 are endemic in over 100 countries, with seasonal outbreaks occurring in northeastern Australia. To mitigate TT-DENV risk in Australia, fresh blood components are not manufactured from donors returning from any area (domestic/overseas) with known dengue transmission. Alternatively, TT-DENV risk may be mitigated using an appropriate blood donor screening assay. We aimed to determine the rate of dengue infection in donors during dengue outbreaks in Australia. Plasma samples were collected from blood donors during local dengue outbreaks. All samples were tested for the presence of DENV RNA and selected samples were tested for DENV antigen (nonstructural protein 1, NS1) with two assays. No donors residing in high risk areas had detectable levels of DENV RNA or NS1 and no cases of DENV viremia were detected in blood donors residing in areas of Australia experiencing DENV outbreaks. Definitive conclusions could not be drawn from this study; however, the lack of detection of DENV RNA or antigen in donations suggests that the current risk of TT-DENV is low and maintaining the fresh component restriction for “at-risk” donors is appropriate.

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BACKGROUND A fatal case of autochthonous Babesia microti infection was reported in Australia in 2012. This has implications for Australian public health and, given that babesiosis is transfusion transmissible, has possible implications for Australian blood transfusion recipients. We investigated the seroprevalence of antibodies to B. microti in Australian blood donors and in patients with clinically suspected babesiosis. STUDY DESIGN AND METHODS Plasma samples (n = 7,000) from donors donating in at‐risk areas and clinical specimens from patients with clinically suspected babesiosis (n = 29) were tested for B. microti IgG by immunofluorescence assay (IFA). IFA initially reactive samples were tested for B. microti IgG and IgM by immunoblot and B. microti DNA by polymerase chain reaction. RESULTS Although five donors were initially reactive for B. microti IgG by IFA, none was confirmed for B. microti IgG (zero estimate; 95% confidence interval, 0%–0.05%) and all were negative for B. microti DNA. None of the patient samples had B. microti IgG, IgM, or DNA. CONCLUSIONS This study does not provide evidence for widespread exposure to B. microti in Australian blood donors at local theoretical risk, nor does it provide evidence of B. microti infection in Australian patients with clinically suspected babesiosis. Given that confirmed evidence of previous exposure to B. microti was not seen, these data suggest that transmission of this pathogen is currently uncommon in Australia and unlikely to pose a risk to transfusion safety at present.