Immunology USMLE Step 1 Practice Question
A 20-year-old male with stridor is brought to the emergency department by his girlfriend. He had been complaining of abdominal pain earlier in the day. Physical examination is significant for well-demarcated regions of subcutaneous edema. He has had similar episodes before, and his mother and sister have the same condition. Which of the following substances is most likely deficient in this patient?
Answer choices
- AFactor H
- BCarboxypeptidase
- CC1 esterase inhibitorCorrect answer
- DC3b inactivator
- EProperdin
- FKallikrein inhibitor
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.