Modulation of Dendritic Cell IL-6 and TNF-α Production in an In Vitro Model of Red Blood Cell Transfusion — ASN Events
  1. Schedule
  2. Poster Session 1
  3. Modulation of Dendritic Cell IL-6 and TNF-α Production in an In Vitro Model of Red Blood Cell Transfusion

Modulation of Dendritic Cell IL-6 and TNF-α Production in an In Vitro Model of Red Blood Cell Transfusion (#99)

Katrina KK Ki 1 2 , Robert RF Flower 2 , Helen HF Faddy 1 2 , Melinda MD Dean 2
  1. School of Medicine , University of Queensland , St Lucia , QLD , Australia
  2. Australian Red Cross Blood Service, Kelvin Grove, QLD, Australia

Introduction
Packed red blood cell (PRBC) transfusion has been associated with increased rates of infectious complications, morbidity and mortality. PRBC are stored for up to 42 days post collection and there is evidence that adverse patient outcomes are associated with increasing length of storage of PRBC prior to transfusion. Currently, the mechanisms driving transfusion-related immune modulation (TRIM) remain largely undefined. The production of cytokines and chemokines by dendritic cells (DC) is critical for the initiation and regulation of the immune response. To address potential mechanisms of TRIM, this study utilised an in vitro transfusion model to investigate changes in cytokine and chemokine responses in DC subsequent to exposure to fresh (day (D)2) and stored (D42) PRBC.

Methods
The “transfusion recipient” was modelled by fresh whole blood collected from volunteers (n=4). A 25% volume replacement “transfusion” was established by culture of fresh or stored leukodepleted PRBC, with an ABO compatible recipient (5½ hours, 37°C, +1ug/mL Brefeldin A). Lipopolysaccharide (LPS) was added to replicate wells to model the immune response to bacterial infection. Myeloid DC (mDC) production of IL-6, IL-8, IL-10, IL-12 and TNF-α was measured by intracellular staining and flow cytometry. Analysis of variance (ANOVA, Tukey post-test) was used to asses changes in inflammatory mediators compared with matched “no transfusion” controls (p<0.05).

Results
In this transfusion model, in the absence of LPS, there was no difference in DC inflammatory responses following exposure to either fresh (D2) or stored (D42) PRBC. Co-culture with LPS (used as a model of infection) resulted in a significant reduction of mDC production of pro-inflammatory cytokines IL-6 (p=0.009) and TNF-α (p=0.011) with stored (D42) PRBC. This effect was not observed with fresh (D2) PRBC.

Conclusions
These results suggest that transfusion and phagocytic removal of degraded stored PRBC attenuates mDC pro-inflammatory response in a model of infection. Such perturbation of the immune response may contribute to poor patient outcomes in transfusion recipients, particularly those with an underlying infectious complication.