MPO and acute respiratory distress syndrome: Most importantly, pre-treatment of mice with IL17A blocking antibody dramatically alleviated pathological changes associated with PQ-induced ALI, as demonstrated by significant reductions in the W/D ratio (Fig. 2C, P < 0.05), MPO activity (Fig. 2D and Fig. S2A, P < 0.01), and the percentage as well as number of neutrophils infiltrating into the lung tissues (Fig. 2E, P < 0.01) (when compared to mice pre-treated with isotype-matched control rat IgG).