Basement membrane zone - Croatia Flashcards

1
Q

What is the function of integrins?

A

adhesion molecules that link the actin cytoskeleton to molecules of extracellular matrix

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2
Q

What are the main components of the anchoring fibrils in the sublamina densa?

A

collagen VII

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3
Q

Autoimmunity against BPAG2 (BP180, collagen XVII) results in what clinical disease? What species are affected?

A

Bullous pemphigoid – dogs, cats, pigs, horses; Mucous membrane (cicatricial) pemphigoid – dogs, cats; Linear IgA bullous disease – dogs

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4
Q

What breed of dogs is over-represented with mucous membrane pemphigoid?

A

GSDs

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5
Q

What body regions are frequently affected with Epidermolysis Bullosa Acquisita?

A

haired skin in areas of friction – axillae, groin, pinnae, footpads; oral cavity, lips, concave pinnae

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6
Q

In salt-split skin, what proteins will be on the “floor”?

A

laminin-332, collagen VII

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7
Q

In linear IgA dermatosis, anti-BMZ IgA and IgG is detected on which side of salt-split skin (ceiling or floor)?

A

Ceiling – epidermal side (collagen XVII part of hemidesmosome)

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8
Q

Sites of involvement for mixed autoimmune subepidermal blistering disease?

A

haired skin involvement with oral cavity lesions

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9
Q

To what do perlecans bind?

A

themselves, collagen IV, laminin (alpha-chains) – located inside lamina densa

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10
Q

Rowing of individual neutrophils and/or histiocytes along the basement membrane is a common histological feature of what disease?

A

epidermolysis bullosa acquisita

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11
Q

What would be a differential diagnosis for ulcerations at the lips/perilabial area?

A

mucoucutaneous lupus, mucous membrane pemphigoid

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12
Q

Recessive dystrophic epidermolysis bullosa has been reported in what species?

A

humans, white alpine and Assaf sheep, Rotes Hohenvieh and Voderwald cattle, dogs, cats

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13
Q

Mutations in LAMA3 (laminin alpha-3 chain) results in what clinical disease? In what species?

A

Junctional Epidermolysis Bullosa; GSP, American saddlebred horses, Belgian blue cattle

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14
Q

What is the function of keratins in keratinocytes?

A

forms cytoskeleton of epithelial cells

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15
Q

Histopathological features of bullous pemphigoid

A

dermo-epidermal separation (vesicle formation), inflammation in vesicles varible – neutrophils +/- eosinophils; degranulated mast cells in upper dermis

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16
Q

Is plectin part of the outer or inner plaque of the hemidesmosome?

A

inner plaque (intracytoplasmic)

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17
Q

Autoimmunity against laminin-5 has been associated with what clinical disease? In what species

A

Mucous membrane (cicatricial) pemphigoid: humans, one dog; Acquired junctional epidermolysis bullosa: reported in 5 dogs; Mixed subepidermal autoimmune blistering disease (dogs)

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18
Q

Epidermolysis Bullosa Simplex, basal, has been associated with mutations in what genes? In what species?

A

Keratin-5 (KRT5) and plectin (PLEC); KRT5 in Friesian-Jersey cattle, PLEC in a quarterhorse, Eurasier dogs

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19
Q

What is the most common autoimmune subepidermal blistering disease in humans? How common is it in dogs?

A

bullous pemphigoid, rare in dogs – less than 10% of AISBDs

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20
Q

To what does collagen VII bind?

A

laminin-332 (laminin-5), collagen IV, collagen I

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21
Q

To what in the hemidesmosome does collagen IV bind?

A

itself (collagen IV), laminin network via nidogens + fibulins, perlecan

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22
Q

What is the function of nidogens?

A

Link laminins and collagen

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23
Q

Junctional Epidermolysis Bullosa has been reported in what species?

A

lethal variant: humans, dogs, horses, cattle; localized: GSP, American saddlebreds, Belgian blue cattle, draft horses (Belgian, Breton, Comtois and Italian), German black-headed sheep; Intermediate: Charolais cattle, Churra sheep

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24
Q

Acquired junctional epidermolysis bullosa can result from autoimmunity against what structure?

A

Laminin 332 (laminin-5)

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25
Q

Anti-BMZ IgG autoantibodies can be detected in the (ceiling/floor) in Epidermolysis Bullosa Acquisita

A

Floor (target is in lamina densa, i.e. dermis – collagen VII)

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26
Q

Bullous pemphigoid results from autoimmunity against what structures?

A

BP230 (BPAG1-e) = plakin, BP180 (BPAG2, collagen XVII)

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27
Q

To what in the hemidesmosome does BPAG1-e (BP230) bind?

A

keratin intermediate filaments, collagen XVII (cytoplasmic head), integrin beta-4 (carboxyl terminus)

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28
Q

Recessive dystrophic epidermolysis bullosa is associated with mutations in genes that encode for what structures?

A

collagen VII

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29
Q

When keratinocytes start migration from stratum basale to stratum spinosum, what part of hemidesmosome is cleaved?

A

collagen XVII– results in a new protein that lacks a cytoplasmic and transmembrane domain (LAD-1)

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30
Q

What collagens are found in the epidermal basement membrane?

A

collagen XVII, IV and VII

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31
Q

Mutations in the gene that encodes for keratin-5 (KRT5) results in what clinical disease? In what species is it reported?

A

Basal Epidermolysis Bullosa (EB) Simplex variants; cattle

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32
Q

Epidermolysis Bullosa Simplex has been associated with mutations in genes that encode for what molecules?

A

plectin, keratin-5

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33
Q

What in the basement membrane is stained by Periodic Acid-Schiff stain? Why?

A

perlecans, stains polysaccharides (the proteoglycans)

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34
Q

What is LAD-1?

A

cleaved product of collagen XVII that lacks a cytoplasmic and transmembrane domain

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35
Q

Bullous pemphigoid has been reported in what species?

A

dogs, cat (1 case), Yucatan mini-pigs, horses (2-3 cases)

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36
Q

Mutations in COL7A1 (Collagen VII) results in what clinical disease? In what species?

A

Dystrophic Epidermolysis Bullosa; sheep, cattle, dogs, cats, ostrich

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37
Q

T/F: Autoantibodies, predominantly IgG and complement, can be detected along the basement membrane zone in mucous membrane pemphigoid.

A

TRUE

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38
Q

T/F: There are varying phenotypes associated with Dystrophic Epidermolysis Bullosa. Why or why not?

A

True - can have a complete absence of collagen VII or alteration of function (due to truncation of molecules or change in conformation)

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39
Q

Mutations in the gene that encodes for laminin-5 (LAMA3, LAMB3, LAMC2) have been associated with what diseases? In what species?

A

lethal junctional epidermolysis bullosa (dogs, horses, cattle); localized junctional epidermolysis bullosa (LAMA3: German shorthaired pointers, American saddlebreds, Belgian blue cattle), LAMC2: Belgian, Breton, Comtois and Italian draft horses, German black-headed sheep

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40
Q

What is the function of plakins?

A

cytolinkage, can bind multiple types of proteins

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41
Q

What is the most important laminin in the epidermal basement membrane?

A

Laminin-5 (LM332 = 3 alpha chains, 3 beta chains, 2 gamma chains)

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42
Q

T/F: Footpad involvement is commonly seen with both mucous membrane pemphigoid and epidermolysis bullosa acquisita

A

False - only EBA

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43
Q

What therapies have been used in treatment of mucous membrane pemphigoid?

A

glucocorticoids, tetracycline + niacinamide, azathioprine, chlorambucil, mycophenolate, cyclosporine

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44
Q

Mutations in ITGB4 (integrin beta-4) result in what clinical disease? In what species?

A

Junctional Epidermolysis Bullosa; Charolais cattle, Churra sheep

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45
Q

Linear IgA Dermatosis results from autoantibodies to what structure?

A

processed extracellular domain of collagen XVII

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46
Q

What are the two keratins present in the stratum basale keratinocytes?

A

keratin-5 and keratin-14

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47
Q

What is the most common haired skin body region exhibiting skin lesions with mucous membrane pemphigoid in dogs?

A

concave pinna

48
Q

In the single report of bullous systemic lupus erythematosus, which came first, cutaneous subepidermal vesicles or systemic signs?

A

systemic signs

49
Q

T/F: Mucosal involvement in bullous pemphigoid is uncommon.

A

True - primarily a skin-dominant autoimmune subepidermal blistering disease

50
Q

In Epidermolysis bullosa acquisita, staining of salt-split skin with collagen IV results in stain on the top or bottom of the blister?

A

Top – (collagen IV is within the basal keratinocyte), separation is deep (target is collagen VII)

51
Q

Mutations in the gene that encodes for plectin (PLEC) has been associated with what clinical disease(s)? In what specie(s)?

A

Epidermolysis Bullosa Simplex and Laminitis (horses); Epidermolysis Bullosa Simplex (EBS Plectin) in Eurasier dogs

52
Q

What are clinical signs associated with Epidermolysis Bullosa Acquisita?

A

vesicles and bullae, erosions and ulcers, erythematous macules and patches

53
Q

To what family does BPAG1-e (BP230) belong?

A

plakin

54
Q

Junctional Epidermolysis bullosa acquisita results from autoantibodies against what structure(s)?

A

laminin-332 (laminin-5) – the alpha-3 and beta-3 chains

55
Q

What is the common signalment for epidermolysis bullosa acquisita?

A

young animals (median age 1.2 years), Great Danes over-represented

56
Q

T/F: Systemic signs are commonly reported with mucous membrane pemphigoid.

A

False – signs reflect location of lesions (i.e. oral cavity pain, reduced appetite, halitosis, etc.)

57
Q

What are clinical lesions associated with mucous membrane pemphigoid?

A

erosions/ulcers (#1), intact vesicles/bullae, scarring (infrequent)

58
Q

T/F: Both circulating and tissue-bound autoantibodies can be detected in Epidermolysis bullosa acquisita.

A

TRUE

59
Q

Genetic mutations in genes ITGB4 (encodes for integrin beta-4) have been associated with what disease(s) in what specie(s)?

A

Junctional Epidermolysis Bullosa, generalized intermediate (JEB-gen intermed) in Charolais calves and Churra sheep

60
Q

To what in the hemidesmosome does integrin alpha-6/beta-4 bind?

A

outer plaque, alpha-6 chain: NC16A extracellular domain of collagen XVII (BPAG2, BP180); beta-4 chain: cytoplasmic carboxyl terminus binds to head of collagen XVII, plectin, BPAG1-e; aminal terminus of both chains binds laminin-5 and laminin-10 (inner plaque)

61
Q

What are the main components of the anchoring filaments?

A

collagen XVII (BPAG2, BP180)

62
Q

Autoantibodies in canine mucous membrane pemphigoid have been detected against what structures?

A

collagen XVII (BPAG2, BP180), BP230 (BPAG1e), laminin-332 (laminin-5)

63
Q

Synonyms for Collagen XVII

A

BPAG2, BP180

64
Q

Bullous systemic lupus erythematosus clinically resembles what other disease?

A

epidermolysis bullosa acquisita

65
Q

What are the epidermal plakins found in hemidesmosomes?

A

BPAG-1, plectin

66
Q

T/F: Mucous membrane pemphigoid is confined to the mucosae and mucocutaneous junctions.

A

False - the skin can be affected with minor lesions (10-30% of cases have skin lesions)

67
Q

What is the mode of transmission of inherited epidermolysis bullosa?

A

autosomal recessive

68
Q

What are anchoring filaments?

A

connect hemidesmosomes to anchoring fibrils throughout the lamina lucida

69
Q

What is the difference in autoantigen between canine Junctional Epidermolysis Bullosa Acquisita and traditional EBA?

A

JEBA - laminin-332, EBA- collagen VII

70
Q

What are the sites of attachment of keratin filaments?

A

nucleus (nuclear laminin B), desmosome, hemidesmosome, other keratin intermediate filaments

71
Q

Canine mixed autoimmune subepidermal blistering disease clinically resembles what other disease?

A

bullous pemphigoid

72
Q

Mutations in LAMC2 (laminin gamma-2 chain) results in what clinical disease? In what species?

A

Junctional Epidermolysis Bullosa; draft breed horses of European origin (Breton, Comtois, Belgian), German black-head mutton sheep, Danish Herefords

73
Q

In what species has epidermolysis bullosa acquisita been reported?

A

humans, dogs

74
Q

What is the most common autoimmune subepidermal blistering disease in dogs?

A

mucous membrane pemphigoid

75
Q

To what in the basement membrane zone does laminin-332 bind?

A

alpha-3 binds integrin alpha-6/beta-4, beta-3 binds to NC1 domain of collagen VII, BPAG2 (collagen XVII)

76
Q

Autoantibodies in mixed Autoimmune subepidermal blistering disease have been detected against what structures?

A

laminin-332 AND collagen VII

77
Q

Mucous membrane pemphigoid can result from autoimmunity against what structures?

A

BP230 (BPAG1-e)= plakin, BP180 (BPAG2, collagen XVII) - NC domain and carboxyl terminus

78
Q

Histopathological features of epidermolysis bullosa acquisita

A

dermo-epidermal separation (vesicle formation), inflammation in vesicles varible – neutrophils +/- eosinophils; early lesions - subepidermal vacuoles with rowing of neutrophils +/- histiocytes along BMZ

79
Q

In salt-split skin, what diseases will result in stain uptake (i.e. autoantibodies) in either the roof or the floor?

A

mucous membrane pemphigoid, Junctional EBA

80
Q

What are the main components of the inner plaque of the hemidesmosome?

A

plectin + BPAG1-e

81
Q

What are the main components of a collagen domain?

A

triads of glycine-amino acid 1- amino acid 2

82
Q

Epidermolysis Bullosa Acquisita can result from autoimmunity against what structure?

A

collagen VII (NC domain)

83
Q

Junctional Epidermolysis Bullosa has been associated with mutations in what genes?

A

ITGB4 (integrin beta-4), laminin 332: LAMA3 (alpha-3 chain), LAMC2 (gamma-2 chain)

84
Q

Besides the skin, where else is collagen IV found?

A

glomerular basement membrane

85
Q

In salt-split skin, what diseases will result in stain uptake (i.e. autoantibodies) in the roof (i.e. epidermis)?

A

bullous pemphigoid, MMP (where target antigen is XVII), linear IgA dermatosis

86
Q

Where are focal contacts present?

A

keratinocyte membrane, lamina densa

87
Q

What clinical diseases in animals have been associated with mutations in EPPK1 or autoantibodies against epiplakin-1?

A

none

88
Q

What distinguishes junctional epidermolysis bullosa from epidermolysis bullosa simplex, basal?

A

clefting occurs above perlecan or between alpha-6 integrin and collagen IV (above lamina densa) in junctional EB

89
Q

T/F: Systemic signs are commonly reported with epidermolysis bullosa acquisita.

A

True– pruritus, pain, lethargy, fever, lymphadenopathy, anorexia

90
Q

Mutations in the gene that encodes for collagen VII (COL7A1) results in what clinical disease? In what species?

A

Recessive Dystrophic Epidermolysis Bullosa (RDEB, various subtypes) – white alpine and Assaf sheep, Rotes Hohenvieh and Voderwald cattle, dogs, cats

91
Q

Autoimmunity against BPAG1-e (BP230) results in what clinical disease?

A

Bullous pemphigoid (dogs); Mucous membrane pemphigoid (dogs); Paraneoplastic Pemphigus (dogs)

92
Q

In what species has acquired junctional epidermolysis bullosa been reported?

A

dogs

93
Q

What are the main components of the lamina densa of the hemidesmosome?

A

collagen IV + laminin + nidogens + perlecan + proteoglycans + fibulins

94
Q

Autoimmunity against collagen VII results in what clinical disease(s)? In what species?

A

Epidermolysis Bullosa Acquisita** (dogs), Type I bullous Systemic Lupus Erythematosus (reported in one dog)

95
Q

What are the main components of the outer plaque of the hemidesmosome

A

integrin alpha-6/beta-4 + cytoplasmic domain of collagen XVII (=BPAG2, BP180)

96
Q

Mixed subepidermal Autoimmune blistering disease can result from autoimmunity against what structure?

A

Laminin 332 (laminin-5)

97
Q

Histopathological features of canine mucous membrane pemphigoid

A

subepidermal or submucosal vesicles – intact usually devoid of inflammation; dermal inflammation usually mild with both neutrophils and eosinophils seen below vesicles or the intact epithelium

98
Q

What is the second most common autoimmune subepidermal blistering disease in dogs?

A

epidermolysis bullosa acquisita

99
Q

Where is the best place to biopsy when an autoimmune subepidermal blistering disease is suspected?

A

ulcer margin with adjacent intact skin

100
Q

Where does plectin bind in the hemidesmosome?

A

keratin intermediate filaments, integrin beta-4 (cytoplasmic tail), collagen XVII (cytoplasmic head)

101
Q

What body sites are commonly affected with mucous membrane pemphigoid?

A

oral cavity, nose/nasal planum, lips, anogenital, periocular, concave pinna

102
Q

To what in the hemidesmosome does collagen XVII (BPAG2, BP180) bind?

A

cytoplasmic side: globular head of collagen XVII interacts with integrin beta-4, plectin, and BPAG1-e; transmembrane section: NC16A (noncollagenous segment) binds to aminal terminus of integrin alpha-6, carboxyterminus binds to laminin-5 (in lamina densa)

103
Q

Junctional Epidermolysis bullosa acquisita in dogs affects what areas of the body?

A

haired skin, footpads, oral mucosa

104
Q

Clinical signs associated with bullous pemphigoid

A

deep erosions/ulcers, erythematous macules/patches/plaques, vesicles/bullae

105
Q

T/F: Both circulating and tissue-bound autoantibodies can be detected in bullous pemphigoid.

A

TRUE

106
Q

What are clinical signs associated with Dystrophic Epidermolysis Bullosa?

A

vesicles (flaccid, clear or hemmorhagic) at mucocutaneous junctions and areas of friction (lips, muzzle, ears, groin, coronary bands, soles, footpads)

107
Q

What are perlecans also known as?

A

heparan sulfate proteoglycan

108
Q

In what species has mixed subepidermal autoimmune blistering disease been reported?

A

dogs

109
Q

T/F: Mucous membrane pemphigoid has been reported in the cat.

A

True - two cats, autoantibodies targeting collagen XVII and laminin-332

110
Q

where in the hemidesmosome-anchoring fibril adhesion complex is collagen IV found?

A

lamina densa

111
Q

What is the common signalment for bullous pempigoid in dogs?

A

middle aged (median age 5 years), daschunds and GSDs reported in 2/9 cases each

112
Q

T/F: Circulating autoantibodies of anti-BMZ proteins are a common feature of mucous membrane pemphigoid.

A

False – low sensitivity

113
Q

Epidermolysis bullosa simplex, suprabasal, has been associated with mutations in what gene? In what species?

A

PKP1 (plakophilin-1), Chesapeake Bay retrievers (caused ectodermal dysplasia-skin fragility syndrome)

114
Q

In salt-split skin, what diseases will result in stain uptake (i.e. autoantibodies) in the floor (i.e. dermis)?

A

Epidermolysis bullosa acquisita, MMP (where target antigen is laminin-332), Junctional EBA, mixed AISBD, bullous SLE

115
Q

Junctional Epidermolysis Bullosa has been associated with mutations in genes that encode for what structures?

A

integrins (beta-4), laminin-5 (laminin 332) - mutations in alpha-3 chain, beta-3 or gamma-2 chain

116
Q

What are focal contacts?

A

inter-hemidesmosomal adhesion structures that are mostly functional during wound healing & epidermal migrations