Pemphigus vulgaris is characterized by acantholysis. Which of the following adhesion molecules is primarily targeted by autoantibodies in this condition?

Explanation

## Autoantigen in Pemphigus Vulgaris **Key Point:** Pemphigus vulgaris is caused by IgG autoantibodies directed against desmogleins, which are transmembrane glycoproteins in desmosomes. ### Desmoglein Targets | Antibody Pattern | Clinical Presentation | Histology | |---|---|---| | Anti-Dsg3 only | Mucosal-dominant PV | Suprabasal acantholysis | | Anti-Dsg3 + Anti-Dsg1 | Mucocutaneous PV | Suprabasal + superficial acantholysis | | Anti-Dsg1 only | Pemphigus foliaceus (NOT PV) | Subcorneal acantholysis | **High-Yield:** In pemphigus vulgaris, the target is **Desmoglein 3 (Dsg3)**, located in the lower epidermis. When anti-Dsg1 antibodies are also present, mucocutaneous disease occurs. The presence of anti-Dsg1 alone defines pemphigus foliaceus, not vulgaris. **Clinical Pearl:** Desmoglein 3 is the "gatekeeper" antigen in PV — its presence is mandatory for diagnosis. Anti-Dsg1 antibodies determine whether the disease is mucosal-dominant or mucocutaneous. **Mnemonic:** **DIP** — **D**esmoglein **I**s **P**rimary in PV. Dsg3 is always present; Dsg1 determines spread to skin.