Host immune response · USMLE Step 1

A patient with CGD (chronic granulomatous disease) has impaired killing of catalase-positive organisms. Which enzyme is deficient?

  1. Myeloperoxidase
  2. Superoxide dismutase
  3. NADPH oxidase
  4. Catalase
Show answer and explanation

Correct answer: NADPH oxidase

CGD results from defective NADPH oxidase, preventing respiratory burst. Catalase-positive organisms neutralize any remaining peroxide.

Difficulty: Medium Question 14 of 20

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