Immunology USMLE Step 1 Practice Question
A 46-year-old man undergoes kidney transplantation. Two weeks post-operatively, he develops hypertension (BP 158/92 mmHg), tachycardia (HR 104/min), and malaise. Serum creatinine rises to 3.2 mg/dL from baseline 1.0 mg/dL. Renal biopsy demonstrates dense interstitial lymphocytic infiltrates with tubulitis. Donor-specific antibodies are not detected on screening. He denies fever and urinalysis shows no proteinuria. Which mechanism best explains these histopathologic findings?
Answer choices
- ARecipient T lymphocytes attack donor major histocompatibility antigens in the graftCorrect answer
- BImmune complexes deposit in the renal interstitium after foreign protein exposure
- CDonor T lymphocytes attack recipient skin, gut, and liver
- DProgressive intimal smooth muscle proliferation due to chronic antibody mediated injury
- EPreformed recipient antibodies bind graft endothelium and activate complement immediately
- FAntibody-mediated rejection from preformed donor-specific antibodies
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