Hypersensitivity, allergy, antihistamines and autoimmunity Flashcards
Anaphylaxis is which type of hypersensitivity?
Type I
Which antibodies mediate anaphylaxis?
IgE
An allergic reaction is provoked by exposure to the sme antigen. True or false?
True
What is the process of coating mast cells with IgE called?
Sensitisation
What are the three types of responses that result from activation of mast cells in type I hypersensitivity?
Rapid release of granule content (degranulation)
Synthesis and secretion of lipid mediators
Synthesis and secretion of cytokines
Allergic asthma, allergic rhinitis and atopic dermatitis are examples of which type of hypersensitivity?
Type I
Which mast cell mediator causes dilation of blood vessels, increases vascular permeability and causes contraction of smooth muscle?
Histamine
What are two examples of type II hypersensitivity?
Haemolytic anaemia
Thrombocytopenia
Which are a side effect of certain drugs
What happens during type II hypersensitivity?
The antibodies produced during the immune response recognise and bind to the antigen, which are structural components of cell surfaces or other tissue
Penicillin, quinidine and methyldopa have been linked to which type of hypersensitivity?
Type II
Which antibodies are involved in type II hypersensitivity?
IgG and IgM
Epinephrine is used for anaphylaxis. True or false?
True
How are the drugs cromlyn and ketotifin used in treatment of type I and II hypersensitivity?
They prevent mast cell degranulation, preventing allergic cascade from happening
Which antibodies are involved in type III hypersensitivity?
IgA, IgE, IgG and IgM
What is type III hypersensitivity as a result of?
Accumulation of antibody-antigen complexes that have not been cleared well by the innate immune system
The immune complexes insert themselves in joints, blood vessels causing symptoms
When IgG binds antigen, complement is activated and C5a is generated which is a chemoattractant and C3b which is a potent opsonin
Phagocytosis - tissue damage
How long does type IV hypersensitivity take to develop?
12 or more hours
What is the main difference between type IV hypersensitivity and and the other types?
Not mediated by antibodies, it is cell-mediated (T-cells and macrophages)
Mycobacterium Tb can induce which type of hypersensitivity?
Type IV
Which type of hypersensitivity does herpes simplex virus cause?
Type iv
In auto-immune disease, antibodies are produced in response to own cells and disease associated with these auto-antibodies are referred to as auto-immune disease. True or false?
True
In myasthenia gravis, what is the auto-antibody produced against?
The Ach receptor - so there is a reduction in the number and so muscle cannot contract
In the form of maturity onset diabetes, what do auto-antibodies cause a reduction in?
The number of insulin receptors
How can insulin-resistant form of diabetes be treated?
Insulin at much higher concentrations than normal so that it can compete with auto-antibodies for the receptor sites
What happens in insulin dependent diabetes?
IgG auto-antibodies fix complement and mediate lysis of insulin producing B cells in the islets of Langerhans in the pancreas
Name three autoimmune diseases
MG
Diabetes
MS
