Bacteriology USMLE Step 1 Practice Question
A 14 month old boy is evaluated for persistent fever and cervical lymphadenitis 6 weeks after receiving the BCG vaccine outside the United States. Culture of a lymph node aspirate grows an attenuated strain of Mycobacterium bovis. He has also had recurrent infections with nontuberculous mycobacteria. Flow cytometry shows normal T cell and B cell numbers. Which of the following immune defects best explains this patient's disease?
Answer choices
- AImpaired response of macrophages to interferon gammaCorrect answer
- BDefective terminal complement activation
- CFailure of VDJ recombination in lymphoid precursors
- DAbsent expression of CD40 ligand on T helper cells
- EInability to form neutrophil extracellular traps
- FIRAK-4 deficiency impairing TLR and IL-1 receptor signaling
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