A skin biopsy from a patient with tense subepidermal blisters shows separation of the epidermis from the dermis at the level of the lamina lucida. Immunofluorescence reveals linear IgG against a transmembrane component of the structure that anchors basal keratinocytes to the underlying basement membrane. Which junction is the target of these autoantibodies?

• A Desmosome, targeting desmoglein 3
• B Hemidesmosome, targeting BP180 (type XVII collagen) ✓
• C Focal adhesion, targeting vinculin
• D Gap junction, targeting connexin 26

Explanation

Hemidesmosomes anchor the basal keratinocyte cytoskeleton to the basement membrane through integrin alpha 6 beta 4 and BP180 (collagen XVII), and antibodies against BP180 define bullous pemphigoid, producing tense subepidermal blisters splitting within the lamina lucida. Desmoglein 3 antibodies cause pemphigus vulgaris, an intraepidermal, flaccid blistering disease with suprabasal acantholysis, which contradicts the subepidermal split described here. Connexin 26 forms gap junction channels involved in hearing, not adhesion.

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.