This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
Herpes gestatioinalis is 
Select and explain. 
A. Caused by Herpes virus, B. Autoimmune reaction to collagen XVII in  basement membrane of skin, C. Neutrophilic degranulation at dermal - epidermal junction, D. Less severe in subsequent pregnancies.
B: Autoimmune reaction to collagen XVII in  basement membrane of skin
Answer: B: Autoimmune reaction to collagen XVII in  basement membrane of skin 
Explanation: Herpes gestationalis (pemphigoid gestationis ) is characterized by eosinophilic degranulation at dermal-epidermal junction. Becomes severe with subsequent pregnancies.