091614 basement membrane Flashcards

1
Q

structure of basement membrane zone

A

hemidesmosome
lamina lucida
lamina densa
sublamina densa

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2
Q

in pts with inherited blistering diseases, what is the basis?

A

genes encoding some structural proteins of the basement membrane zone are mutated

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3
Q

BP 230

A

bullous phemphigoid antigen 1

from the plakin family of proteins
cytoplasmic localization
important for cytoskeletal organization

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4
Q

BP 180

A

bullous pemphigoid antigen 2
also known as type XVII collagen

transmembrane protein that connects basal keratinocytes through BP 230 to the cytoskeleton and through laminin 332 to dermal collagen VII

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5
Q

bullous pemphigoid (BP)

A

tense blisters (fluid could be clear or hemorrhagic)

antibody binding to BP antigens causes subepidermal separation

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6
Q

BP is the most common

A

autoimmune bullous dermatosis

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7
Q

BP occurs primarily in whom

A

elderly

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8
Q

stages of BP

A

early: highly pruritic urticaria w/o blistering
later: tense blisters with serous or rarely hemorrhagic content (very stable blisters in contrast to pemphigus groups of diseases)

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9
Q

antibodies in BP are directed against what?

A

BP 230 and BP 180

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10
Q

generalized atrophic benign epidermolysis bullosa

A

mutated BP 180 protein

synonyms are collen type XVII and bullous pemphigoid antigen 2

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11
Q

clinical presentation of generalized atrophic benign epidermolysis bullosa

A

blisters

loss of hair

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12
Q

lamina lucida

A

immediately underlies hemidesmosomes

LL may be an artifact of tissue prep and dehydration

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13
Q

lamina densa

A

composed mostly of type IV collagen (one of the most abundant collagens of the BMZ) and laminins

key laminin is laminin 332 (prev known as laminin 5)

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14
Q

what makes up more than 1/2 of the mass of the BMZ

A

type IV collagen

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15
Q

what does laminin 332 do?

A

laminin 332 binds to hemidesmosomal protein integrin alpha6beta4 on the basal keratiocytes and to type VII collagen in the dermis, providing adhesion

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16
Q

mucous membrane pemphigoid predominantly affects whom

A

older ppl

17
Q

mucous membrane pemphigoid

A

recurrent blistering of mucous membranes (also skin)

development of scars, strictures, synchiae(iris sticks to lens or cornea), and blindness

majority of pts have Ig against BP 180 (some have Ig against BP230, integrin beta4, laminin 332)

18
Q

what subtype of MMP has an association with malignancies?

A

anti-laminin 332 pemphigoid

19
Q

Herlitz junctional EB

A

defect in laminin 332

20
Q

laminin 332

A

prev known as laminin 5

21
Q

sublamina densa

A

type VII is composed of 3 identical alpha chains

22
Q

type VII collagen is important for what?

A

to maintain epidermal dermal cohesion, b/c it binds to both type I and type IV collagens

23
Q

epidermolysis bullosa acquisita

A

autoantibodies against type VII collagen

rare autoimmune bullous dermatosis
slight trauma elicits blistering and erosions of skin

often there’s involvement of oral mucosa-hemorrhagic erosions

24
Q

where does epidermolysis bullosa acquisita affect most?

A

mechanically stressed areas

25
Q

inherited epidermolysis bullosa

A

mutations in genes encoding BMZ proteins
skin fragility

erosions after minimal trauma

26
Q

types of inherited epidermolysis bullosa

A
EB simplex (keratin 5, 14)
junctional EB (laminin, BP180, integrins)
dystrophic EB (type VII collagen)
kindler syndrome (kindlin 1)
27
Q

direct immunofluorescence

A

detects Ig and C3
samples are from pt perilesional skin

antibodies are against human Ig or complement

28
Q

indirect immunofluorescence

A

detects circulating Ig against BMZ in the pt’s serum

serum is applied to foreign substrate such as normal human skin, monkey esophagus, rodent bladder