Inflammation of skin Flashcards
Describe the role of Langerhan cells [3]
Dendritic cell - spine-like projections
Efficient at presenting antigen to CD4+ helper T-cell
Pick up antigens that enter the skin and transport them to the lymph node
Staining dendritic cells n epidermis in a patient with skin infection.
Describe what type of infection each of the following are predominately involved with:
Th17 cells [2]
Th1 cells [3]
Th2 cells [2]
Th17 cells: extracellular bacteria and fungi
Th1 cells: intracellular bacteria, protozoans and viruses
Th2 cells:helminths
What do each of the following cause the creation of
Th17 cells [1]
Th1 cells [1]
Th2 cells [4]
Th17 cells
* IL17
Th1 cells [1]
* IFN-y
Th2 cells [2]
* IL-4
* IL-5
* IL-13
* IL-25
Describe pathway of mast cell degranulation after exposure to an antigen [3]
APC picks up the antigen and presents to the T cell.
Th2 produces IL4 & IL5, which activates the B cells to make IgE, which then activate the mast cell and degranulation occurs
IgE producition- produced after a second exposure.
What do mast cells release into systemic circulation? [4]
histamine, leukotrienes, prostaglandins,
platelet aggregating factor
State 5 physiological effects of mast cell degranulation [5]
leaky blood vessels
bronchoconstriction
Intestinal hypermotility
inflammation
tissue remodelling
Histamine is important as it causes which symptoms seen in an allergic reaction? [6[
Smooth muscle contraction
Vessel leak and oedema
Bronchospasm
Arteriole dilatation causing headache and hypotension
Modulation of immune response via H2 receptors
Name an allergen produced by dust mice [3]
How does it cause damage to airway epithelium? [1]
Der P1 is an enzyme allergen
from the faecal pellets
of the dust mite.
Der P1 breaks down components of tight junctions which helps it to cross mucosa.
Binds to mast cells and causes degranulation
Describe anaphylaxis occurs [2]
Generalised: antigen released into blood stream, binds to IgE on basophils: massive release of inflammatory mediators- bronchospasm and circulatory collapse
Name this sign [1]
What is the most common cause of it? [1]
Urticaria:
Urticaria describes a local (or generalised) superficial swelling of the skin
The most common cause of urticaria is allergy although non-allergic causes are seen.
Antigen released into blood stream, binding to IgE on basophils and causing massive release of inflammatory mediators, bronchospasm and circulatory collapse is called? [1]
Anaphylaxis
How can you treat resistant urticaria and asthma?
Omalizumab: binds free IgE in the serum, forming trimers and hexamers
Explain the different methods of Antibody Mediated Inflammation [4]
Complement medicated lysis
Phagocytosed by extravascular macrophages
Anti-body dependent cell mediated cytotoxicity
Receptor blockage
What is Pemphigus Vulgaris? [2]
autoimmune disease caused by antibodies directed against desmoglein 3, a cadherin-type epithelial cell adhesion molecule
Antibody and complement binds to desmoglein 3: causes acantholysis (loss of coherence between epidermal cells due to the breakdown of intercellular bridges)
Features of Histology of Pemphigus Vulgaris? [2]
Suprabasal splitting in PV
Acantholysis - loss of cohesion
between epidermal keratinocytes
How do you diagnose pemphigus vulgaris? [2]
Dilute patient serum: take normal epidermis and stain with patients serum stained with flourscent antibody
Diluted pemphigus vulgaris serum binds to normal epidermis at
intercellular junctions (where desmogleins are localised)
Describe the features of Immune Complex Mediated Vasculitis [4]
Antigen and antibody form an immune complex
This causes production of proteins and aggregation of platelets into micro thrombi
This results in:
* Deposition of fibrin
* Leaky vessel and extravasation of blood and oedema.
* The proteases degrade vessel BMZ
* Necrosis of the vessel wall
Name this disease [1]
Leukocytoclastic Vasculitis: Blood induced- there are black and necrotic areas on the legs.
Describe the histoligical features of Leukocytoclastic Vasculitis? [2]
fibrin in blood vessel,
nuclear dust
Name three examples of allergic contact dermatitis [3]
Nickel- jewellery, watch straps, zips
Rubber- elastic in clothing
Topical antibiotics
Primula
Allergic Contact Dermatitis pathogenesis? [3]
Promotion of Th1 response:
- Secretion of IL2, IL3, GM-CSF, IFNg and TNF
- This promotes a macrophage rich response
- Causes inflammation to the skin around 48 hours to 72 hours after the challenge
Describe formation of granulomas
Clonal T-cell expansion
Secretion of
Th1 cytokines:
IL-2, IFN-g, TNF causes the creation of macrophages
Name this disease [1]
Sarcoidosis
Name this disease [1]
Lupus Vulgaris- Cutaneous TB
Explain why an autoimmune reaction occurs [1]
Name two causes of autoimmune skin inflammatory diseases
An autoimmune disease occurs when the immune system fails to recognise the body’s own tissue as ‘self’ and mounts an attack on it.
Alopecia Areata (AA)
Vitiligo
Vitiligo
What is this? [1]
[sarcoid] granuloma
Which cells are stained in this histological slide of the epidermis? [1]
Staining of dendritic cells in epidermis in a patient with skin infection.
This histological slide shows which skin pathology? [1]
Pemphigus Vulgaris: acantholysis - loss of cohesion
between epidermal keratinocytes
This histological slide shows which skin pathology? [1]
Suprabasal splitting in Pemphigus vulgaris
What pathology is depicted in this slide? [1]
Leukocytoclastic Vasculitis: fibrin in blood vessel, nuclear dust
