rIL-35 prevents murine transfusion-related acute lung injury by inhibiting the activation of endothelial cells.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is an important cause of death associated with transfusion, and no specific clinical treatments are available. Endothelial cells are believed to play an important role in the development of TRALI. This study investigated whether IL-35, an endothelial stabilizing cytokine could regulate the severity of antibody-mediated TRALI in vivo. STUDY DESIGN AND METHODS: Human microvascular endothelial cells (HMVECs) were cultured in vitro, rIL-35(2 µg/mL) was added before HMVECs activation, and HMVECs were fully activated by LPS (0.5 µg/mL). Then cells were collected for flow cytometry analysis. We used a previously established "two-event" mouse model of TRALI with naive and lipopolysaccharide (LPS)-injected mice as controls. rIL-35(100 µg/kg) was injected into the tail vein for 3 consecutive days before the induction of the TRALI model. Samples were collected 2 hours after TRALI induction and tested for lung tissue myeloperoxidase activity, total protein levels, lung tissue histology, endothelial cell activation assay, and cytokine assay. RESULTS: In vitro culture of HMVECs with rIL-35 verified that rIL-35 inhibited endothelial cells. In a mouse model, prophylactic administration of rIL-35 prevented pulmonary edema, increased lung protein levels, and reduced polymorphonuclear neutrophil accumulation in the lung. CONCLUSIONS: This work suggests that antibody-mediated murine TRALI can be prevented by rIL-35, and that rIL-35 appears to work by inhibiting the activation of lung endothelial cells.

The ATP-gated P2X1 ion channel contributes to the severity of antibody-mediated Transfusion-Related Acute Lung Injury in mice.

The biological responses that control the development of Transfusion-Related Acute Lung Injury (TRALI), a serious post-transfusion respiratory syndrome, still need to be clarified. Since extracellular nucleotides and their P2 receptors participate in inflammatory processes as well as in cellular responses to stress, we investigated the role of the ATP-gated P2X1 cation channel in antibody-mediated TRALI. The effects of NF449, a selective P2X1 receptor (P2RX1) antagonist, were analyzed in a mouse two-hit model of TRALI. Mice were primed with lipopolysaccharide (LPS) and 24 h later challenged by administrating an anti-MHC I antibody. The selective P2RX1 antagonist NF449 was administrated before the administration of LPS and/or the anti-MHC I antibody. When given before antibody administration, NF449 improved survival while maximal protection was achieved when NF449 was also administrated before the sensitization step. Under this later condition, protein contents in bronchoalveolar lavages were dramatically reduced. Cell depletion experiments indicated that monocytes/macrophages, but not neutrophils, contribute to this effect. In addition, the reduced lung periarteriolar interstitial edemas in NF449-treated mice suggested that P2RX1 from arteriolar smooth muscle cells could represent a target of NF449. Accordingly, inhibition of TRPC6, another cation channel expressed by smooth muscle cells, also reduced TRALI-associated pulmonary interstitial and alveolar edemas. These data strongly suggest that cation channels like P2RX1 or TRPC6 participate to TRALI pathological responses.