Effects of blocking CD11/CD18 subunits on the transendothelial migration of patient versus control neutrophils. Neutrophils were treated with saturating concentrations of mAbs against CD18 (MHM23), CD11a (TS1/22), and CD11b (60.1) or a control cell-binding mAb before evaluating transendothelial migration (TEM) as described earlier. As for Figure 6, TEM by the patient's neutrophils was markedly diminished compared with controls. For control neutrophils, blocking CD18 almost completely inhibited TEM, and blocking CD11a also markedly reduced TEM. However, blocking CD11b produced only a modest inhibition. For patient neutrophils, all 3 mAbs produced virtually complete inhibition of TEM. Error bars indicate SEM.