On biopsy, which immunofluorescence pattern is characteristic of pemphigus vulgaris?

On biopsy, which immunofluorescence pattern is characteristic of pemphigus vulgaris?

• A. Granular IgA in dermal papillae
• B. Net-like intercellular IgG
• C. No immunofluorescence
• D. Linear IgG along basement membrane

Answer: (B)

Pemphigus vulgaris is driven by autoantibodies against desmosomal proteins in the epidermis, which disrupt keratinocyte adhesion and cause intraepidermal blisters (acantholysis). On direct immunofluorescence, IgG (often with C3) deposits are found in the intercellular spaces between epidermal cells, producing a net-like (fishnet) pattern throughout the epidermis. This intercellular IgG pattern is the hallmark of pemphigus vulgaris. Other patterns point to different diseases: granular IgA in dermal papillae suggests dermatitis herpetiformis, linear IgG along the basement membrane suggests bullous pemphigoid, and no immunofluorescence would be inconsistent with PV.

Pemphigus vulgaris is driven by autoantibodies against desmosomal proteins in the epidermis, which disrupt keratinocyte adhesion and cause intraepidermal blisters (acantholysis). On direct immunofluorescence, IgG (often with C3) deposits are found in the intercellular spaces between epidermal cells, producing a net-like (fishnet) pattern throughout the epidermis. This intercellular IgG pattern is the hallmark of pemphigus vulgaris. Other patterns point to different diseases: granular IgA in dermal papillae suggests dermatitis herpetiformis, linear IgG along the basement membrane suggests bullous pemphigoid, and no immunofluorescence would be inconsistent with PV.