Blistering skin disorders 3 Flashcards
Where is desmoglein 1 mainly expressed?
At the surface–> granular layer
Where is desmoglein 3 mainly expressed?
At the basal layer
Which molecules are expressed throughout the epidermis?
Plakophilin 3 (PKP3)
Why are the splits in the two types of pemphigus in different places?
The autoantibodies are targeting different places in the epidermis
Ways to diagnose pemhpigus?
Clinical picture, histology, direct and indirect immunofluorescence, ELISA
Clinical picture of pemphigus?
Flaccid lesions/blisters
What staining is done in pemphigus histological testing?
H&E
What is looked for in pemphigus histological testing?
Epidermal acantholysis
What is the direct immunofluorescence aimed at when looking for pemphigus?
Detect IgG autoantibodies in the skin, and C3 pericellular deposits
Why is C looked for in immunofluorescent staining for pemphigus?
Complement system is activated by IgG autoantibodies
What does the indirect immunofluorescence test need?
Blood serum
How does the indirect immunofluorescence test work?
Incubate blood serum with epithelial substrate
MEasures desmogleins in the blood serum
ELISA test for pemphigus?
Immunoassay for human IgG to detect specific autoantibodies
What kind of disease is bullous pemphigoid?
Autoimmune
What is seen in bullous pemphigoid?
Sub-epidermal blistering causing robust blisters
Where is the split in bullous pemphigoid?
Base of the epidermis, below the basal layer
Between the epidermis and the dermis
What do the autoantibodies in bullous pemphigoid recognise?
Hemidesmosomal components
WHich hemidesmosomal components are recognized by the bullous pemphigoid ?
BP180 (collagen XVII) (more common)
BP230 (intracellular plakin)
Where is the separation (scientific name) in bullous pemphigoid?
Dermo-epidermal junction
Role of BP180?
Linking the basal keratinocytes to the basement membrane
Layers of the basement membrane?
Lamina lucida, lamina densa, sublamina densa
What does a lack of BP180 cause?
Prevention of attachment of basal keratinocytes to basement membrane
Which attachment protein is BP180 involved with?
Hemidesmosomes
Facilitating factors that cause autoimmunity in blistering skin diseases?
Drugs, viral infections, physical agents
How do Drugs, viral infections, physical agents cause autoimmunity?
Change the immune response or alter antigenic properties of epidermal antigens
Cross reactivity of antigens?
One harmful antigen from an organism may be similar to one in our body. The body makes antibodies to the harmful antigen and then those antibodies react against our antigen
P. foliaceous cross reactivity?
protein in sand fly in Tunisia is similar to desmoglein 1–> many people in tunisia have P. foliaceous
When is Pemphigoid gestationis seen?
Pregnancy
Other than in in the hemidesmosomes, where is BP180 expressed?
placental tissues (cytotrophoblastic cells).
Why do maternal immune system produce antibodies against BP180?
Partial placental breakdown
WHat can increase the risk of Pemphigoid gestationis?
MHC II class HLA antigens DR3 and DR4
