**Core Concept**
Pemphigus is a group of autoimmune skin diseases characterized by the formation of blisters on the skin and mucous membranes. The disease is caused by the production of autoantibodies against proteins that play a crucial role in maintaining the integrity of the skin's epidermal layer.

**Why the Correct Answer is Right**
The correct answer, Desmoglein 1&3, refers to the specific proteins that are targeted by autoantibodies in pemphigus. Desmoglein 1 and 3 are transmembrane adhesion molecules that help to hold skin cells together. In pemphigus, autoantibodies bind to these proteins, leading to their degradation and the disruption of intercellular adhesion, which ultimately results in the formation of blisters. The presence of autoantibodies against Desmoglein 1 is typically seen in pemphigus foliaceus, while autoantibodies against Desmoglein 3 are commonly found in pemphigus vulgaris.

**Why Each Wrong Option is Incorrect**
**Option A:** Desmoglein 1&2. While Desmoglein 1 is indeed targeted in pemphigus, autoantibodies against Desmoglein 2 are more commonly associated with mucous membrane pemphigoid, a different autoimmune disease.
**Option C:** Desmoglein 1&4. Desmoglein 4 is not typically targeted by autoantibodies in pemphigus.
**Option D:** Desmoglein 2&4. As mentioned earlier, Desmoglein 2 is more commonly associated with mucous membrane pemphigoid, and Desmoglein 4 is not typically targeted in pemphigus.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the presence of autoantibodies against specific desmogleins can help differentiate between various autoimmune skin diseases. For example, the presence of autoantibodies against Desmoglein 1 is highly suggestive of pemphigus foliaceus, while autoantibodies against Desmoglein 3 are more commonly seen in pemphigus vulgaris.

**✓ Correct Answer: B. Desmoglein1&3.**