Pemphigus DIF Pattern — ORE Part 1 MCQ

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HardOral PathologyPemphigus DIF PatternORE Part 1

A patient has oral lesions and histopathological features consistent with pemphigus vulgaris. A perilesional oral mucosal biopsy is submitted for direct immunofluorescence. Which pattern is most likely?

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Correct answer: D — Intercellular IgG in a reticular fish-net pattern

**A is correct.** In pemphigus vulgaris, pathogenic autoantibodies target desmosomal adhesion proteins on keratinocytes, especially desmoglein 3. On direct immunofluorescence of perilesional mucosa, this produces intercellular IgG staining throughout the epithelium, giving the classic reticular “fish-net” or “chicken-wire” appearance. Oral-biopsy evidence demonstrates intercellular IgG deposition in almost all cases of oral pemphigus vulgaris. **B** is the classic linear basement-membrane-zone pattern of pemphigoid, often with C3. **D** instead suggests linear IgA bullous dermatosis. **C** is the granular papillary IgA pattern of dermatitis herpetiformis. **E** is not the characteristic DIF pattern for pemphigus vulgaris. The decisive distinction is intercellular epithelial staining, rather than linear or granular deposition at the basement membrane zone.

Reference: Laskaris GL. Oral pemphigus vulgaris: an immunofluorescent study of fifty-eight cases. Oral Surgery, Oral Medicine, Oral Pathology, 1981. https://pubmed.ncbi.nlm.nih.gov/6942362/