African American control (AA) or steady-state SCD (SS) human whole blood with or without LPS pretreatment was perfused through micro-channels presenting P-selectin, ICAM-1, and IL-8; and neutrophil-platelet interactions were monitored using quantitative microfluidic fluorescence microscopy (qMFM) over a 2-minute period. (A) Total platelet interactions with arrested neutrophils in SCD (steady state) whole blood with or without pretreatment with 0.25 μg/ml of LPS. Representative of 6 experiments with 6 SCD subjects. (B) Total platelet interactions with arrested neutrophils in control human blood with or without pretreatment with 0.25 or 1 μg/ml LPS. Representative of 6 experiments with 5 control subjects. (C) Comparison of total platelet-neutrophil interactions following pretreatment of control and SCD blood with 0.25 μg/ml LPS. Representative of 8 experiments with 3 control and 5 SCD subjects. (D and E) Effect of TAK-242 and/or intralipid (vehicle) pretreatment on (D) the total number of platelet interactions with arrested neutrophils and (E) total number of arrested neutrophils over a 2-minute observation period in 0.25 or 1 μg/ml LPS–treated SCD or control human blood, respectively. TAK-242 was added to the blood (50 μg/ml) and incubated for 5 minutes. After 5 minutes, LPS was added to the blood and incubated for 10 minutes before perfusion through the micro-channels. Representative of 6 experiments with 3 control and 3 SCD subjects. Data represent mean ± SEM. ^#P < 0.05 when comparing with baseline; ⁺P < 0.05 when comparing with TAK-242. Means were compared using Student’s t test with Bonferroni correction. Each data point represents a single field of view (FOV), and observations were made over multiple FOVs in some experiments. See Supplemental Methods for details. Wall shear stress: 6 dyn/cm². FOV: ~14,520 μm².