In pemphigus vulgaris, DIF of perilesional skin shows IgG and C3 in an intercellular (chicken-wire) pattern throughout the epidermis. The antibody titre correlates with disease activity. Using indirect immunofluorescence (IIF), the best substrate to detect these antibodies is:

• A Salt-split human skin
• B Guinea pig lip
• C Rat bladder epithelium
• D Monkey oesophagus ✓

Explanation

For indirect immunofluorescence (IIF) of pemphigus antibodies targeting desmogleins (Dsg1 and Dsg3), monkey oesophagus is the classic and most sensitive substrate, showing the intercellular 'fish-net' or 'chicken-wire' staining pattern. Guinea pig lip has been used historically and is good for Dsg1. Rat bladder/esophagus is used as substrate in some settings. Salt-split human skin is used for BMZ antibody characterisation (pemphigoid vs. EBA). ELISA for specific anti-Dsg1/Dsg3 antibodies is now the preferred quantitative method.

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.