Immunobullous dz Flashcards
What is the primary function of the epidermis?
The keratinocytes and dendritic cells are the primary cells involved in microbial defense
Keratinocytes:
how do they recognize antigens
what do they produce?
They display Pattern Recognition Receptors
keratinocytes produce cytokines (IL-1, 6, 8, and TNF), defensins, and prostaglandins
* they may also respond to cytokines in conditions like psoriasis
Langerhans:
what is their role?
APC cells (shaped like dendrites). They have both MHC class I and II, CD40, CAMs, and B7.
The contain birbeck granules which are involved in receptor mediated endocytosis and participate in antigen processing and presenting
what are the resident cells of the dermis?
macrophages, lymphocytes, dendritic cells.
during a response to antigens, other cells are recruited from circulation to contribute to the elimination of the microbe, and/or the production of skin lesions
What is the sensitization phase of the immune response?
Sensitization:
the antigen is taken up by teh APC and carried to the lymph nodes → present the processed antigen to naive T cells → activate antigen specific lymphocytes. Many of these cells head back to the skin where they may reside as memory cells
What happens in the effector phase of the immune response?
In the effector phase:
Cell mediated immune response. Subsequent contact with an antigen elicits the effector phase by activating resident cutaneous CD8 and CD4 T cells (effector memory T cells)
This is like the secondary phase of a systemic immune response
Widespread blisterin of skin and or mucus membranes.
(+) Nikolsky sign
Mediterranean descent
What is the most likely diagnosis?
Pemphigus vulgaris or pemphigus foliaceus
autoantibody IgG against DSG1 and DSG3 that causes blisters in the deep subasal epidermis
What is the most likely diagnosis?
Pemphigus vulgaris
tx with corticosteroids or azathioprine
strong assoc w/ HLA-DR allele
autoantibody IgG against Dsg1 alone that leads to subcorneal blisters.
IF shows IgG surrounding keratinocytes in a “fish net” appearance
Pemphigus foliaceus
Dsg1 and Dsg3 are functionally interchangable components of desmosomes (found in the epidermis)
tx with corticosteroids or azathioprine
strong assoc w/ HLA-DR allele
What is the mostly likely diagnosis?
What is the most likely diagnosis?
tense blisters that do NOT rupture easily
Bullous Pemphigoid
IgG and C3 deposits at the dermal-epidermal junction.
The C3 attracts neutrophils leading to the accumulation of neutrophil and eosinophil infiltrates and skin separation.
the oral mucosa is spared
an autoimmune (IgG Ab) destruction of the hemidesmosome in the basement membrane leads to a blister between?
the dermis and the epidermis
This is Bullous Pemphigoid
Dermatitis Herpetiformis
pathology?
what other conditions is it associated with?
Dermatitis Herpetiformis
IgA deposits at the dermal-epidermal junction (tips of the dermal papillae) + neutrophil accumulation at the tip of the papillae which leads to tiny blisters e
This condition is associated w/ gluten-sensitive enteropathy (celiac disease)
This condition is associated with IBD
the skin has a positive nikolsky sign
very rare
Subepidermal
Lineral pattern of IgG binding
What is the most likely diagnosis?
What is the target of the antigen?
Epidermolysis bullosa acquisita
target antigen = type VII collagen
the fluid filled blisters usually occure in response to friction (elbows, knees, butt)
