A 60-year-old man has tense blisters over the flexures. DIF shows linear IgG and C3 at the dermoepidermal junction. The target antigen is located in which part of the basement membrane zone?
- A Lamina lucida — BP180 (BPAG2/collagen XVII) ✓
- B Lamina densa
- C Sub-lamina densa — anchoring fibrils
- D Lamina densa — collagen IV network
Correct answer: A. Lamina lucida — BP180 (BPAG2/collagen XVII)
Explanation
Bullous pemphigoid targets BP230 (BPAG1, intracellular plaque of hemidesmosomes) and BP180 (BPAG2/collagen XVII, transmembrane collagen in lamina lucida). IgG against the NC16A domain of BP180 is the most clinically significant antibody. Collagen VII (anchoring fibrils in sub-lamina densa) is targeted in epidermolysis bullosa acquisita. Linear IgA disease targets LAD-1, a shed ectodomain of BP180.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.