In dermatitis herpetiformis (DH), the characteristic DIF finding is granular IgA in the dermal papillae. The antigen recognised by these IgA antibodies is:

• A Desmoglein-1
• B BPAG-180 (BP180)
• C Laminin-332
• D Epidermal transglutaminase (TG3/eTG) ✓

Explanation

In dermatitis herpetiformis, IgA autoantibodies target epidermal transglutaminase (TG3, also called eTG), which is distinct from tissue transglutaminase (TG2) targeted in coeliac disease serology. These IgA-eTG immune complexes deposit in dermal papillae, triggering neutrophil recruitment and subepidermal microabscess formation. The fundamental trigger is gluten sensitivity. BP180 is targeted in bullous pemphigoid; Desmoglein-1 in pemphigus foliaceus; Laminin-332 in mucous membrane pemphigoid (a subset).

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.