A pregnant woman at 30 weeks develops intensely pruritic urticarial papules and plaques, then tense blisters, starting around the umbilicus. DIF shows linear C3 with or without IgG at the BMZ. The target antigen is:
- A BP230 (BPAG1)
- B Collagen VII (anchoring fibrils)
- C BP180 NC16A domain (collagen XVII) ✓
- D Laminin-332 (epiligrin)
Correct answer: C. BP180 NC16A domain (collagen XVII)
Explanation
Pemphigoid gestationis (herpes gestationis) targets the NC16A domain of BP180 (collagen XVII, type XVII collagen), identical to the antigen in bullous pemphigoid. The condition shares pathogenesis with BP and is driven by MHC class II-restricted IgG1 antibodies crossing to the fetal skin. C3 deposition is characteristically more prominent than IgG on DIF. Fetal risks include small-for-gestational-age and neonatal blistering.
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.