A 55-year-old man presents with painful, persistent oral erosions involving the buccal mucosa and tongue. Ocular examination reveals conjunctival scarring and symblepharon. DIF of perilesional oral mucosa shows linear IgG and C3 at the basement membrane zone. Salt-split skin shows IgG on the floor. Which antigen is most likely targeted?

• A BP180 (collagen XVII)
• B Laminin 332 (laminin 5) ✓
• C BP230
• D Type VII collagen

Explanation

Mucous membrane pemphigoid with scarring and ocular involvement (symblepharon) with floor binding on salt-split suggests anti-laminin 332 (laminin 5) mucous membrane pemphigoid. This subtype carries risk of malignancy. BP180 and BP230 are targets in bullous pemphigoid and some MMP cases but typically show roof binding. Type VII collagen is targeted in epidermolysis bullosa acquisita, which also shows floor binding but lacks the mucosal scarring pattern described.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.