44. A 10-year-old boy with aa history ofof recurrent bacterial infections and aldetaysoot delayed separation of the umbilical cord is found to have markedly decreased neutrophil adesiooe adhesion to endothelium on laboratory testing. Which step ofleukocyte recruitment in acute inflammation is most directly impaired in this patient?
(A) Vasodilation mediated by histamine and nitric oxide
(B) Margination of leukocytes in postcapillary venules
(C) Chemotaxis toward bacterial products
(D) Firm adhesion due to defective integrins (LAD type 1)