Stored red blood cells selectively activate human neutrophils to release IL-8 and secretory PLA2

Packed red blood cell (PRBC) transfusion has been invoked previously with immunosuppression and increased infections, but it has now been demonstrated that stored PRBCs (>14 days) can prime PMNs and provoke multiple organ failure. Recently, the role of PMNs in the genesis of MOF has been extended to their release of inflammatory cytokines, notably IL-1, IL-8, TNF alpha, and secretory phospholipase A(2) (sPLA(2)). We hypothesize that stored PRBCs can act as a second event via stimulating the release of inflammatory cytokines from PMNs. Isolated human PMNs were incubated for 24 h in RPMI with either 20% fresh plasma or plasma from 42 day old PRBC (day of outdate) and release of IL-8, IL-1 beta, TNF alpha, and sPLA(2) were measured. Plasma from stored PRBCs contained small amounts of IL-8, sPLA(2), and TNF alpha (102.1 +/- 5.6 pg/ml, 87.6 +/- 6.0 pg/ml and 9.7 +/- .7 pg/ml), Levels of IL-1 beta were below detection (<1 pg/ml). Day 42 PRBC plasma stimulated significant PMN release of both IL-8 and sPLA(2) as compared to both control and day 0 plasma (*P < .05), but PRBC plasma did not stimulate PMN release of either IL-1 beta or TNF alpha. Transfused blood is emerging as an inflammatory agent that is capable of producing PMN priming. In this study we have demonstrated that PRBC plasma selectively activates PMNs to release both IL-8 and sPLA(2). Thus, transfusion of PRBCs may represent a preventable inflammatory insult via modification of both blood banking and transfusion practices.