The target antigen responsible for the linear IgG and C3 deposition along the basement membrane zone in bullous pemphigoid is located primarily at which site within the hemidesmosome?

• A BP230, an intracytoplasmic plakin of the inner hemidesmosomal plaque
• B BP180 (type XVII collagen), a transmembrane hemidesmosomal component extending into the lamina lucida ✓
• C Type VII collagen of the sublamina densa anchoring fibrils
• D Alpha-6 beta-4 integrin extracellular domain

Explanation

BP180, also called type XVII collagen, spans the basal keratinocyte membrane with its collagenous ectodomain projecting into the lamina lucida, making it the major pathogenic antigen of bullous pemphigoid; antibodies here explain the roof pattern on salt-split skin. BP230 is intracellular and not directly accessible, type VII collagen is the target of epidermolysis bullosa acquisita lying beneath the lamina densa, and alpha-6 beta-4 integrin relates to junctional EB with pyloric atresia.

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.