skip to main content

MMP Immunofluorescence — MFDS Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

HardOral PathologyMMP ImmunofluorescenceMFDS Part 1

A 68-year-old woman has persistent desquamative gingivitis and recurrent oral bullae without significant cutaneous involvement. Histopathological examination of a lesional biopsy demonstrates a subepithelial cleft. Which direct immunofluorescence finding in a perilesional mucosal biopsy would most strongly support mucous membrane pemphigoid?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Continuous linear IgG and C3, with or without IgA, along the basement membrane zone

The correct answer is C. Mucous membrane pemphigoid produces a subepithelial split, while direct immunofluorescence characteristically demonstrates continuous linear deposition of IgG, IgA and/or C3 along the basement membrane zone. IgG and C3 are commonly detected; predominant or exclusive IgA staining may raise classification as linear IgA disease. Granular papillary-tip IgA is associated with dermatitis herpetiformis. Reticular intercellular IgG is the characteristic epithelial pattern of pemphigus vulgaris, which causes intraepithelial rather than subepithelial separation. Shaggy fibrinogen with IgM cytoid bodies supports oral lichen planus. Granular basement-membrane and vascular IgG/C3 staining is more consistent with a lupus-band pattern.

Reference: Schmidt E, et al. European Guidelines (S3) on diagnosis and management of mucous membrane pemphigoid, Part II: diagnostic work-up and direct immunofluorescence, 2021. https://pubmed.ncbi.nlm.nih.gov/34309078/