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Pathology · single question

Mucous membrane pemphigoid (MMP) affects which cellular structure, causing subepithelial blistering?

  1. Gap junctions (intercellular communication channels)
  2. Tight junctions (endothelial cell barriers)
  3. Desmosomes (intercellular connections between keratinocytes)
  4. Hemidesmosomes (anchoring basal epithelial cells to basement membrane zone)
Show answer and explanation

Correct answer: D. Hemidesmosomes (anchoring basal epithelial cells to basement membrane zone)

  • A. Gap junctions allow intercellular communication — not a target in MMP.
  • B. Tight junctions are cell-to-cell barriers in epithelium and endothelium — not targeted in MMP.
  • C. Desmosomes (desmoglein 1 and 3) are the targets in PEMPHIGUS VULGARIS — causing INTRAEPITHELIAL (suprabasilar) blistering and acantholysis. Nikolsky sign is positive.
  • D. Correct. MMP is an autoimmune disease where IgG (and sometimes IgA) antibodies target components of the HEMIDESMOSOME complex — specifically type XVII collagen (BP180), BP230, and laminin-332. Hemidesmosomes anchor basal epithelial cells to the basement membrane zone. Their destruction causes SUBEPITHELIAL separation (blister forms BELOW the epithelium, which comes off as an intact sheet).

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