Week 5 Flashcards
What are ROS components?
Reactive oxygen species
Where are IgA antibodies found?
In mucous, saliva, tears and breast milk.
What do IgA antibodies protect against?
Pathogens
Where are IgD antibodies found?
Part of the B cell receptors.
What are the main function of IgD antibodies?
Activate basophil and mast cells.
What are IgE antibodies responsible for?
Allergic reactions.
Where are IgG antibodies secreted from ?
Plasma cells in the blood.
Can IgG antibodies cross the placenta?
Yes
Where are IgM antibodies found?
Attached to the surface of B cells or in the blood.
What is the onset time of type 1 hypersensitivity?
5-15 minutes
What antibodies mediate type 1 hypersensitivity?
IgE
What hypersensitivity type are most allergic reactions?
1
What causes an allergy?
There is a genetic component to an allergy where the individual has certain genes that make their T cells more hypersensitive to certain antigens.
How do type 1 allergens enter the body?
They are breathed or taken in.
Contact with the skin.
What is an allergen?
An antigen that causes an allergic reaction.
What are the symptoms of type 1 hypersensitivity?
Rhinitis Conjunctivitis Hives Angiodema Asthama Anaphylaxis
What is angiodema?
Swelling of deeper layers of the skin caused by a build-up of fluid.
How many times do you need to be exposed to an allergen to become allergic?
2
On the first exposure you become sensitive and on the second you can have more severe reactions.
What are the possible treatments for type 1 hypersensitivity reactions?
Adrenaline
Antihistamines
Corticosteroids
What are some of the clinical features of asthma?
- Reversible generalised airway obstruction.
- Chronic Episodic wheeze.
- Bronchial hyperresponsivness.
- Bronchial irritability cough.
- Mucus production.
- Breathlessness
- Chest tightness
- Reduced variable peak flow.
Outline how Asthma is treated.
- Beta-1 Agonist drugs can be required by inhalation.
- Inhalation of a steroid of a low-moderate dose.
- Long acting Beta-2 agonists and Leukotriene agonists may be inhaled in high doses if needed.
- Oral steroids.
How do beta-2 agonists and leukotriene antagonists work to treat asthma?
They block the degranulation of receptors that activation constriction of airways.
What are the symptoms of Rhinitis?
Sneezing Rhinnorehoea Itchy nose and eyes Nasal blockage and Sinusitis Loss of smell and taste
What is the common name for Rhinitis?
Hay-fever
How is allergic Rhinitis treated?
Anti-histamines
Nasal steroids
Cromoglycate
What type of Rhinitis patients is Cromoglycate given to and why?
Children to help the eyes.
What is anaphylactic shock?
A severe generalised allergic reaction which is uncommon but can be fatal.
What are the clinical symptoms of anaphylactic shock?
- Generalised degranulation of IgE sensitised mast cells.
- Cardiovascular effects such as vasodilation and cardiovascular collapse.
- Respiratory effects such as bronchospasm and laryngeal oedema.
- Skin effects such as vasodilation, erythema, urticarial and angioedema.
- GI effects such as vomiting an diarrhoea.
What is Erythema?
Redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries.
What is Urticarial ?
Hives
What is Angioedema?
An area of swelling of the lower layer of skin and tissue just under the skin or mucous membranes
What are the symptoms of anaphylactic shock?
- Itchiness around the mouth and lips.
- Swelling of the lips and throat.
- Wheezing
- Chest tightness
- Dyspnoea
- Faintness
- Collapsing
- Diarrhoea
- Vomiting
What is Dyspnoea ?
Difficulty with breathing.
What type of sensitivity is type 2 hypersensitivity?
Cytotoxic
Outline what type 2 hypersensitivity is
Antibody mediated destruction of healthy cells by central tolerance.
What is the central tolerance that occurs in type 2 hypersensitivity?
Immune cells that are self-reactive are destroyed and this leads to autoimmunity.
What are the possible mechanisms of type 2 hypersensitivity ?
-Complement - cytotoxic.
Intrinsic antigen MAC - cytotoxic.
-Complement opsonisation - cytotoxic.
-Antibody dependent cell mediated cytotoxicity.
-Antibody-mediate cellular destruction - non-cytotoxic.
Outline the Cytotoxic complement mechanism of type 2 hypersensitivity.
- Penicillin binds to red blood cells, IgG against penicillin binds and forms a complex.
- C1 binds to Fc portion of Ab.
- C1 activates the complement cascade and chemotactic factors are released which attract Neutrophils.
- Neutrophils degranulate and release MPO which kills cells.
Outline the Cytotoxic intrinsic antigen MAC method of type 2 hypersensitivity.
Activation of complement leading to C5b and C6-9 combining to form a membrane attack complex.
MAC penetrates the membrane causing lysis.