Basement Membrane Zone and Vesiculobullous Diseases Flashcards
What are the 4 parts of the Basement Membrane?
1) the plasma membrane and hemidesmosomal plaques of the basal keratinocyte
2) lamina lucida
3) lamina densa
4) sublamina densa
What is BPAG-2?
a transmembrane protein made up of XVII collagen
Binds to BPAG1 and integrins (in hemidesmosomes) with laminin 5 located in the laminin 5 located in the lamina densa
What is BPAG-1?
an intracytoplasmic protein located within the cytoplasm of the basal keratinocyte hemidesmosomes
binds to keratin intermediate filaments to stabilize the cell
What layer of the basement membrane does the BPAG-2 transverse?
lamina lucida
What is the lamina densa composed of?
Laminins and collagen IV
What is the key laminin found in the BMZ?
laminin 5
Where is Type IV collagen located?
lamina densa
What type of collagen is found in the sublamina densa?
Type VII
What are immunobullous diseases?
inflammation of cells in the epidermis or BMZ
Leads to loss of cell-to-cell adhesion and subsequent bulla formation
What are congenital mechanobullous diseases?
There is an absence of structural proteins that prevent normal cell-cell adhesion and promotes blister formation.
What is the Nikolsky sign?
Apply gentle pressure to the edges of a blister and pull laterally to determine if a bulla is flaccid or tense
Where is a DIF sample taken from?
perilesional site
What is IIF?
It tests serum for circulating antibodies
A serological test (DIF) for pemphigus vulgaris is testing against what?
IgG antibodies directed against Dsg 1 and 3
A serological test (DIF) for bullous pemphigoid is testing against what?
BPAG1 and 2
Describe common features of Pemphigus vulgaris
autoimmune blistering disease characterized by flaccid bullae and erosions
oral erosions
crusting of scalp
PAINFUL
what will you see histologically in PV?
the basal keratinocytes remain connected to the BMZ resulting in a “tombstoning” appearance
What is the treatment for PV?
systemic steroids and immunosuppressents
Describe common features of Bullous Pemphigoid (BP)
typically affects adults 60+
itching
tense bullae
What does a DIF of BP reveal?
a linear staining of the basement membrane with IgG and C3
also seen in CP
What is the treatment for BP?
high potency topical steroids and oral antibiotics; severe cases may require immunosuppressants
Describe common features of Cicatrical Pemphigoid (CP)
90% have oral symptoms, 66% have ocular symptoms, and 25 skin (flaccid bullae)
chronic
PAINFUL
what is the treatment for CP?
potent topical corticosteroids and oral immunosuppressants
What are antibodies directed against in CP?
BPAG2 and laminin 5
What causes inherited mechanobullous diseases?
congenital absence of proteins in the BMZ
What is Epidermolysis Bullosa (EB)?
a group of diseases with bullae and mechanical fragility of the skin
What is Epidermyolysis Bullosa simplex?
an autosomal dominant disease where epidermal keratins are absent
What is junctional Epidermyolysis Bullosa?
An autosomal recessive disease with laminin and BPAG2 mutations in the lamina densa
What is dystrophic Epidermyolysis Bullosa?
an autosomal dominant and recessive disease where collagen VII is absent or abnormal
Why does Epidermyolysis Bullosa have a high mortality rate?
increased risk of squamous cell carcinoma
What disease is associated with celiac disease?
Dermatitis Herpeitiformis (DH)
What is the treatment for DH?
gluten-free diet and dapsone (sulfa-based antibiotic)
what are some common features of Dermatitis Herpetiformis (DH)?
affects individuals of northern descent
Very itchy
affects the occipital scalp, extensor upper and lower extremities and buttocks
lesions are papules, vesicles, and urticarial plaques
What cancer of DH patients at risk of contracting?
gastric lymphoma (6%)
