PMC9374178_01
Clinical findings. (A, B) Patient clinical presentation at age 68 following disease worsening: blisters, erosions, and crusts with an erythematous halo are scattered on the back and thorax. Note linear erythematous lesions (arrowheads) on the lateral thorax in (B) due to scratching. (C, D) Clinical manifestations at age 69 when the patient was on bullous pemphigoid (BP) remission under minimal corticosteroid therapy. Note the absence of active lesions on the trunk, while skin erosions and atrophic scarring with milia, typical of localized recessive dystrophic epidermolysis bullosa, are visible on elbows.
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Physical examination revealed numerous blisters, erosions, and crusts surrounded by erythematous skin (Figures 1A, B). The patient is currently in remission for BP with minimal steroid therapy (10 mg/day) (Figures 1C, D).
Immunofluorescence antigen mapping, and ultrastructural and molecular genetic findings. (A) Labeling intensity for type VII collagen is reduced in the patient's skin (bottom panel) as compared to control skin (top panel). Bar = 40 microm. (B) Ultrastructural examination shows a few, hypoplastic anchoring fibrils (arrowheads) inserting onto the lamina densa of the cutaneous basement membrane zone in patient's skin. Bar = 1 microm. (C) Detection of the c.3G>T (top panel) and c.8054G>C (middle panel) compound heterozygous mutations by Sanger sequencing of the patient's genomic DNA (gDNA). The sequence of the complementary DNA (cDNA) across the c.8054G/C nucleotide position is also shown (bottom panel). Note that only transcripts carrying the c.8054C variation are detected.
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IF antigen mapping and electron microscopy were performed. IF mapping showed a slightly reduced expression of C7, which was localized to the roof in areas of dermal-epidermal detachment (Figure 2A). Ultrastructural examination showed a reduced number of hypoplastic anchoring fibrils, which mostly lacked cross-banding (Figure 2B). DNA with an exome panel approach (TruSight One expanded, Illumina, San Diego, CA, USA). Datasets retrieved from the 16 EB genes revealed two variants in COL7A1: c.3G>T and c.8054G>C (Figure 2C, top and middle panels). REVEL) supports a deleterious effect on the gene product (PP3). Reverse transcriptase (RT)-PCR analysis of the mRNA extracted from patient keratinocytes identified molecules transcribed only from the c.8054C allele (Figure 2C, bottom panel).
Direct and indirect immunofluorescence findings. (A) Linear deposit of IgG along the dermal-epidermal junction by direct immunofluorescence on patient's perilesional skin. In the magnified inset, the 'n' serrated pattern further supports the bullous pemphigoid diagnosis. (B) Indirect immunofluorescence on salt-split skin with patient's serum shows IgG binding to the roof of the split (white arrows). Bar = 40 microm.
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IF (DIF) was also performed. It showed a continuous linear deposition of IgG along the BMZ (Figure 3A). Subsequent testing of the patient's serum by indirect IF on salt split skin (IIF-SSS) revealed linear IgG along the roof of separated skin at a titer of 1:40 (Figure 3B).
Timeline of patient's clinical history, and diagnostic and therapeutic steps.
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