Pemphigus vulgaris is characterized by all, except:
**Core Concept**
Pemphigus vulgaris is an autoimmune disease characterized by the formation of blisters on the skin and mucous membranes due to the breakdown of skin adhesion caused by autoantibodies against desmoglein 3 proteins, which are components of desmosomes.
**Why the Correct Answer is Right**
The disease is caused by autoantibodies that target the intercellular connections between keratinocytes, leading to the loss of cell-to-cell adhesion. This results in the formation of suprabasal blisters and subsequent separation of the epidermis, causing the characteristic skin lesions. Desmoglein 3 is a key target antigen in pemphigus vulgaris.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because pemphigus vulgaris is indeed characterized by the presence of autoantibodies against desmoglein 3 proteins.
* **Option B:** This option is incorrect because pemphigus vulgaris is indeed characterized by the formation of suprabasal blisters and subsequent separation of the epidermis.
* **Option D:** This option is incorrect because pemphigus vulgaris is indeed characterized by the breakdown of skin adhesion caused by autoantibodies against desmoglein 3 proteins.
**Clinical Pearl / High-Yield Fact**
Pemphigus vulgaris is often associated with other autoimmune diseases, such as lupus erythematosus and rheumatoid arthritis. A thorough review of the patient's medical history and physical examination is essential for making an accurate diagnosis.
**Correct Answer: A.**