Stored red blood cells selectively activate human neutrophils to release IL-8 and secretory PLA(2)

Packed red blood cell (PRBC) transfusion has been invoked previously with i mmunosuppression and increased infections, but it has now been demonstrated that stored PRBCs (>14 days) can prime PMNs and provoke multiple organ fai lure. 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, an d secretory phospholipase A(2) (sPLA(2)). We hypothesize that stored PRBCs can act as a second event via stimulating the release of inflammatory cytok ines from PMNs. Isolated human PMNs were incubated for 24 h in RPMI with ei ther 20% fresh plasma or plasma from 42 day old PRBC (day of outdate) and r elease of IL-8, IL-1 beta, TNF alpha, and sPLA(2) were measured. Plasma fro m 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 signifi cant PMN release of both IL-8 and sPLA(2) as compared to both control and d ay 0 plasma (*P < .05), but PRBC plasma did not stimulate PMN release of ei ther IL-1 beta or TNF alpha. Transfused blood is emerging as an inflammator y agent that is capable of producing PMN priming. In this study we have dem onstrated that PRBC plasma selectively activates PMNs to release both IL-8 and sPLA(2). Thus, transfusion of PRBCs may represent a preventable inflamm atory insult via modification of both blood banking and transfusion practic es.