A 2-year-old boy presents with recurrent skin and mucosal bacterial infections, delayed umbilical cord separation at 6 weeks of life, and fever (38.5°C). Vital signs show HR 110/min, RR 28/min, BP 95/62 mmHg. Laboratory studies reveal WBC 18,500/μL with marked neutrophilia. Despite purulent infection, minimal pus forms at infected sites. Flow cytometry demonstrates absent CD18 expression on neutrophils. Which step of the acute inflammatory response is primarily impaired?
- A)Phagolysosome fusion
- B)Generation of reactive oxygen species
- C)Rolling mediated by selectins
- D)Opsonization by IgG and C3b
- E)Firm adhesion of neutrophils to endotheliumGABARITO
Explicação
CD18 is the beta 2 integrin subunit required for leukocyte adhesion deficiency type 1. Without functional integrins, neutrophils cannot achieve firm adhesion to endothelial ICAM molecules, so they remain in the circulation, producing neutrophilia with little p... Ver explicação completa e trilha adaptativa →