In pemphigus vulgaris, antibodies are present against:
**Core Concept**
Pemphigus vulgaris is an autoimmune disease characterized by the formation of blisters on the skin and mucous membranes. It occurs due to the presence of autoantibodies against desmoglein proteins, which are essential components of the desmosomes that hold skin cells together.
**Why the Correct Answer is Right**
In pemphigus vulgaris, the autoantibodies target desmoglein 3 (Dsg3) proteins, which are found in the epidermis. The binding of these autoantibodies to Dsg3 disrupts the intercellular connections between keratinocytes, leading to the loss of cell-cell adhesion and the formation of blisters. This process is often mediated by the activation of complement and the subsequent release of inflammatory mediators.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option may seem plausible, but it is incorrect because pemphigus vulgaris specifically targets desmoglein 3, not desmoglein 1. Desmoglein 1 is targeted in pemphigus foliaceus, a different autoimmune disease.
* **Option B:** This option is incorrect because pemphigus vulgaris does not involve the presence of antibodies against laminin. Laminin is a component of the basement membrane, which is not directly involved in the pathogenesis of pemphigus vulgaris.
* **Option D:** This option is incorrect because pemphigus vulgaris does not involve the presence of antibodies against collagen. Collagen is a major component of the skin's extracellular matrix, but it is not directly targeted in pemphigus vulgaris.
**Clinical Pearl / High-Yield Fact**
Pemphigus vulgaris is often associated with the presence of mucosal lesions, particularly in the oral cavity. The presence of oral lesions is a key distinguishing feature of pemphigus vulgaris from other autoimmune bullous diseases.
**Correct Answer:** C.