Activating and inhibitory arms of neutrophil activation. E-selectin–mediated adhesion activates Src kinases, which then leads to the up-regulation of the leukocyte integrin Mac-1 at the leading edge of crawling neutrophils. GMI-1070 works principally by inhibiting E-selectin–mediated activation. Polarized expression of activated Mac-1 allows the capture of erythrocytes. IVIG administration works by binding to FcγRIII expressed on neutrophils, leading to the recruitment of SHP-1 that inhibits Mac-1 activation.