Elevation of C-reactive protein levels in patients with transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related fatalities and is characterized by the onset of acute respiratory distress within six hours following blood transfusion. In most cases, donor antibodies are suggested to be involved, however, the pathogenesis is poorly understood. A two-hit model is generally assumed to underlie TRALI pathogenesis where the first hit consists of a patient predisposing factor such as inflammation and the second hit is due to donor antibodies present in the transfused blood. We recently demonstrated that the acute phase protein C-reactive protein (CRP) could enhance murine anti-major histocompatibility complex (MHC) class I-mediated TRALI. Whether CRP is increased in human TRALI patients which would support its role as a risk factor for human TRALI, is currently unknown. For that purpose, we measured CRP levels in the plasma of human TRALI patients and found CRP levels to be significantly elevated compared to transfused control patients. These data support the notion that CRP may be a novel first hit risk factor in human TRALI and that modulation of CRP levels could be an effective therapeutic strategy for this serious adverse event of transfusion.