Inflammation and Immune Pathology USMLE Step 1 Practice Question
A 41-year-old woman with rheumatoid arthritis treated with etanercept presents with productive cough, fever (38.9°C), and dyspnea. Vital signs show BP 128/82, HR 102, RR 22, SpO2 92% on room air. Chest X-ray reveals bilateral lower lobe infiltrates. Sputum culture grows acid-fast bacilli; tuberculin skin test is negative. She denies night sweats. Which mechanism best explains her increased susceptibility to this infection despite appropriate TNF-alpha inhibitor dosing?
Answer choices
- ALoss of TNF-alpha-mediated Th1 differentiation and granuloma maintenance impairing mycobacterial controlCorrect answer
- BInhibition of B cell maturation preventing antibody production
- CComplement pathway inhibition reducing opsonization of mycobacteria
- DBlocking of IL-4 signaling reducing Th2 cell differentiation
- EDirect antibody-mediated destruction of alveolar macrophages by etanercept
- FImpaired neutrophil chemotaxis and reduced production of antimicrobial peptides in the respiratory tract
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