Inflammation and Immune Pathology USMLE Step 1 Practice Question
A 28-year-old woman presents with a 6-month history of progressive dry eyes and dry mouth. She has a past medical history of Hashimoto thyroiditis diagnosed 3 years ago. Physical examination reveals decreased tear production on Schirmer test and parotid gland enlargement. Laboratory studies show positive anti-muscarinic-3 receptor antibodies, positive rheumatoid factor, and elevated ESR. Salivary gland biopsy demonstrates dense lymphocytic infiltration with germinal center formation and destruction of acinar tissue. Which of the following best explains the mechanism of acinar cell destruction in this patient?
Answer choices
- AIgE-mediated mast cell degranulation releasing proteolytic enzymes
- BIgG antibodies binding to cell surface receptors and blocking their function without causing cell lysis
- CIgG antibodies binding to tissue antigens, fixing complement, and recruiting cytotoxic cells
- DAutoreactive T cells directly infiltrating and destroying tissue via perforin and granzyme release
- EImmune complex deposition in ductal basement membrane activating the alternate complement pathway
- FIgM and IgG antibodies against tissue-specific antigens with complement-mediated and antibody-dependent cellular cytotoxicityCorrect answer
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.