Metabolism USMLE Step 1 Practice Question
A 3 year old boy is brought to the emergency department with fever and lethargy. Blood cultures later grow Streptococcus pneumoniae. He has had multiple episodes of invasive pyogenic bacterial infection since infancy, but extensive immunologic evaluation shows normal neutrophil count, normal oxidative burst, and normal immunoglobulin levels. Viral and fungal infections have been uncommon. Defective signaling through which of the following is the most likely cause of this patient's condition?
Answer choices
- ACD28 on naive T cells
- BClass I major histocompatibility complex molecules
- CB cell receptor associated tyrosine kinase
- DTerminal complement components C5 through C9
- EToll like receptors that activate NF kappa BCorrect answer
- FFc receptors on macrophages and neutrophils
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