23 - Skin Inflammation

Question 1

Cardinal signs of inflammatin

Answer 1

Heat
Redness
Swelling
Pain

Question 2

Langerhans cells

Answer 2

In the epidermis
Dendritic cells - spine like projections
Pick up antigens that enter the skin and transport to the lymph nodes

Question 3

What type of sensitivity is Mast Cell Mediated Inflammation

Answer 3

Type 1 hypersensitivity

Question 4

What are the steps in Mast Cell mediated inflammation

Answer 4

1) Allergen ingested by APCs which present to allergen to cells
2) TH2 T cells recognise and produce 1L-4
3) IL-4 promotes B-cells –> plasma cells
4) Plasma cells release IgE antibodies
5) IgE antibodies bind to Fc receptor on mast cell
6) 2nd exposure - allergen binds to IgE
7) Mast cell degranulates when all binds

Question 5

What is released from a mast cell in mast cell degranulation

Answer 5

Histamines
Cytokines
Enzymes
Prostaglandins 
Leukotrienes

Question 6

Function of histamine

Answer 6

Smooth muscle contraction
Bronchoconstriction
Intestinal hypermotility
Arteriole dilation - hypotension + headache

Question 7

What is Der P1

Answer 7

Enzyme allergen from faecal pellets of dust mites

Breaks down the components of tight junctions

Question 8

What is mast cell degranulation responsible for

Answer 8

Urticaria
Asthma
Hay fever

Question 9

What causes anaphylaxis

Answer 9

Antigen into blood stream
binds to IgE on basophils
Release of inflammatory mediators
Bronchospasm and circulatory collapse

Question 10

What is omalizumab

Answer 10

Treatment for resistant urticaria and asthma

Question 11

MoA of omalizumab

Answer 11

Binds to circulating IgE to decrease cell bound IgE
Decreases expression of high affinity receptors
Decreases tissue infiltration + mediator release

Question 12

What type of sensitivity is antibody mediated inflammation

Answer 12

T2 hypersensitivity

where antibodies bind to bodies own tissues

Question 13

What is the mechanism of antibody mediated inflammation in pemphigus vulgaris

Answer 13

Antibodies are formed against desmosomes

Lack of cohesion between keratinocytes and epidermiss

Question 14

How do you treat pemphigus Vulgaris

Answer 14

Oral steroids

Question 15

MoA of Rituximab

Answer 15

Targets CD20 on B cells

Question 16

What type of sensitivity is immune complex mediated

Answer 16

Type 3 hypersensitivity

Question 17

How does immune complex mediated work

Answer 17

1) Accumulation of immune complexes (antigen-antibody) that havent been cleared
2) Gives rise to inflammatory response and leukocyte accumulation

Question 18

Where do the immune complexes insert themselves (in type 3 hs)

Answer 18

Blood vessels
Joints
- this causes symptoms

Question 19

Symptoms of early vasculitis

Answer 19

Erythema + oedema

Question 20

Symptoms of established vasculitis

Answer 20

Palpable purpura

Question 21

Severe vasculitis

Answer 21

Ulceration + necrosis

Question 22

What antingen and antibody complex in SLE

Answer 22

DNA

Anti DNA

Question 23

What antigen and antibody complex in Polyarteritis Nodosa

Answer 23

HbsAg

Anti-HBsAb

Question 24

Type of sensitivity is Delayed hypersensitivity

Answer 24

Type 4 hypersensitivity

Question 25

What is the pathophysiology of Allergic Contact Dermatitis

Answer 25

1) Contact allergens can cross the stratum corneum + form a conjugate with a protein
2) Conjugate recognised by langerhans cells as foreign
3) Transported to lymph nodes
4) if meet the allergen again - allergic reaction

Question 26

What is the role of IL-2 and IFN-gamma in ACD

Answer 26

Promote Th1 response- secrease IL2, IL3, GM-CSF, IFN and TNF
Promotes macrophage response
Causes inflammation

Question 27

Examples of contact allergens

Answer 27

Nickel
rubber
topical antibiotics

Question 28

What is granuloma formation

Answer 28

Collection of macrophages (aka histiocytes)

Question 29

Causes of granuloma formation

Answer 29

TB
Sarcoidosis
foreign body granuloma