Experimental filtration mitigates ALI in plasma that contains major histocompatibility complex class I antibodies to OX27. The figure illustrates EBD leak, a measure of ALI, as a function of treatment group. Saline-treated rats (first event) did not demonstrate ALI irrespective of the second event: heat-treated (56°C for 30 minutes) FP, FP with OX27 (FP+OX27), filtered FP (F-FP), or filtered FP + OX27 (FP+OX27). In comparison, endotoxin (LPS) pretreatment did evidence ALI with plasma that contained OX27 (LPS/FP+OX27) as the second event, but no ALI was evident in LPS-treated rats infused with plasma (LPS/FP). Experimental filtration of the plasma with OX27 mitigated ALI (LPS/FP+OX27), and there was no ALI produced by filtered FP (LPS/FP). *P < .05 vs all groups, n = 5. BALF, bronchoalveolar lavage fluid.