A 25-year-old woman presents with tense blisters on her trunk and extremities. Skin biopsy shows a subepidermal blister with the cleavage plane at the dermoepidermal junction. Direct immunofluorescence reveals linear deposits of IgG and C3 along the basement membrane zone. The target antigen is most likely:

• A Desmoglein 3 (transmembrane protein of desmosomes)
• B Desmoglein 1
• C BPAG2 (BP180, type XVII collagen) and BPAG1 in the hemidesmosome ✓
• D Transglutaminase 3 in the papillary dermis

Explanation

Bullous pemphigoid (BP) is the most common autoimmune blistering disorder, characterized by tense subepidermal blisters due to IgG autoantibodies against hemidesmosomal proteins BP180 (BPAG2/type XVII collagen) and BP230 (BPAG1). Linear IgG and C3 along the BMZ on direct immunofluorescence is the diagnostic pattern. Desmoglein 3 is the target in pemphigus vulgaris (intraepidermal blister, flaccid bullae). Desmoglein 1 is targeted in pemphigus foliaceus and fogo selvagem.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.