A 3-year-old boy who received BCG vaccine abroad develops disseminated infection with fever to 38.5°C, HR 108/min, and hepatosplenomegaly. He subsequently presents with recurrent Salmonella bacteremia (blood culture positive). Laboratory evaluation shows normal lymphocyte count of 4,500/μL and normal immunoglobulin levels. He has no history of recurrent pyogenic infections. Which immune defect most likely explains his susceptibility to intracellular pathogens?
- A)Defective terminal complement formation
- B)Defective IL 12 signaling leading to impaired Th1 differentiationGABARITO
- C)Defective class switching due to CD40 ligand deficiency
- D)Defective C1 esterase inhibitor
- E)Defective B cell maturation due to BTK mutation
Explicação
IL 12 is critical for Th1 differentiation and interferon gamma production, which activate macrophages to kill intracellular pathogens. Patients with IL 12 receptor deficiency are susceptible to disseminated mycobacterial and Salmonella infections despite other... Ver explicação completa e trilha adaptativa →