Priming activity of TRALI patient plasma at the time the reaction was recognized compared with activity of fresh plasma from healthy donors, their pretransfusion plasma samples, and buffer-primed controls.

▨ indicates neutrophils preincubated with buffer and ▪ indicates PMNs that were preincubated with WEB 2170 to block the PAF receptor. The plasma-treated groups (fresh, before, and after) were primed with 10% plasma for 5 minutes and then activated with 1 μM fMLP, in contrast to buffer-primed controls. The pretransfusion plasma (before) and posttransfusion plasma samples (after) were drawn from the same patient, the pretransfusion sample prior to the transfusion at the time of blood typing and the posttransfusion sample at the time TRALI was recognized. * indicates a statistically significant (P < .05) difference compared with the fresh plasma, the paired pretransfusion plasma sample, and the buffer-treated control. # indicates a statistically significant (P < .05) difference between PMNs pretreated with WEB 2170 and buffer-treated PMNs. The sample size was 10 for fresh plasma and 34 for the TRALI patients' pre- and posttransfusion samples.