Immunology USMLE Step 1 Practice Question
A 41-year-old man undergoes allogeneic bone marrow transplantation for acute leukemia. Three weeks post-transplant, he develops diffuse maculopapular rash, watery diarrhea, and jaundice. Vital signs show BP 128/82, HR 102, RR 18, Temp 37.8°C. Laboratory studies reveal total bilirubin 3.2 mg/dL and elevated transaminases. Skin biopsy demonstrates lymphocytic infiltration of the epidermis. He denies fever or respiratory symptoms. Which of the following best explains the pathogenesis of his condition?
Answer choices
- ADonor immunocompetent T cells attacking host tissuesCorrect answer
- BImmune complex deposition in skin and liver
- CAutoantibodies against desmogleins
- DIgE mediated mast cell degranulation
- ERecipient antibodies against donor endothelial antigens
- FCytomegalovirus reactivation with direct viral injury to epithelial tissues
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