Topic 6

Question 1

What is an allergy

Answer 1

Allergy is a disorder of immunological reactivity in the form of increased and qualitatively changed immune response, which damages the organism by immune mechanisms.

Question 2

What is Immunoglobin E (IGE)

Answer 2

Immunoglobulin E (IgE) is a type of protein in the body called an antibody. As part of the immune system, it plays a role in allergic reactions. When a person is allergic to a particular substance, such as a food or dust, the immune system mistakenly believes that this usually harmless substance is actually harmful to the body. In an attempt to protect the body, IgE is produced by the immune system to fight that particular substance. This starts a chain of events leading to allergy symptoms. In a person whose asthma is triggered by allergic reactions, this chain of events will lead to asthma symptoms, too.

Question 3

Genetic factors of allergy

Answer 3

T-lymphocytes deficiency or suppression

Lack of formation of IgE

Chromosomal syndrome

Infection

Mutation

Hormonal insufficiency

Type 1 Diebetes affect IgE activity

Question 4

Define Endogenous allergens

Answer 4

This is the body’s own proteins; this may be due to a change of structure caused by physical factors such as cold, heat, ionising radiation.

Question 5

What are the stages of Immediate allergic reaction? (Type 1 hypersensitivity)

Answer 5

Type I hypersensitivity reactions are IgE-mediated reactions that develop rapidly upon exposure to an antigen

These allergens are mainly exogenous allergens (medication, dust mites, animal dander, foods, household chemicals i.e. penicillin, )

Humoral immunity stimulates IgE mediated activation, this causes the release of Mast cells, basophils (circulates blood), and eosinophils (circulate connective tissue) They are members of the granulocyte class of leukocytes because they contain granules rich in chemical mediators such as histamine and heparin.

Mast cells binds to the antigen causing degranulation and release mediators such as histamine, acetylcholine, adenosine, chemotactic mediators, growth factors, and neutral proteases such as chymase and trypsin that lead to generation of kinins.and serotonine.This results in Primary early response: Vasodilation
Vascular damage Smooth muscle spasm this begins within 5 to 30 minutes.

The secondary or late phase of the type I hypersensitivity response occurs 2 to 8 hours after resolution of the initial phase and can last for several days
It results from the action of lipid mediators and cytokines released from mast cells.

The lipid mediators, which are derived from phospholipids found in mast cell membranes, are broken down to form ara- chidonic acid during the process of mast cell degranulation. Arachidonic acid is then utilized in the synthesis of leukot- rienes and prostaglandins, which produce end-organ effects similar to histamine and acetylcholine, except that they have a longer onset and prolonged duration of action. Mast cells also produce cytokines and chemotactic factors that promote migration of eosinophils and leukocytes to the site of allergen exposure, contributing to late-phase response.

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Question 6

List the types of type 1 hypersensitivity

Answer 6

Anaphylaxis shock = associated with the wide- spread release of histamine into the systemic circulation that produces massive vasodilation, hypotension, arterial hypoxia, and airway edema. along with stomach cramps, nausea and vomitting

Cytotoxic allergy= occur when cells within the body are destroyed by antibodies, can be caused by a virus or microbe this caused a change in the structure of ones antigens.

Immune complex= This an abnormal immune resonse to the antigen. This can be due to exogenous and enogenous factors

Question 7

List a delayed allergy

Answer 7

Transplant rejection

Contact dermatitis examples cosmetics, hair dyes, metals, topical drugs, plant oils

Question 8

Define Autoallergy/ autoimmune agression

Answer 8

This is due to the body’s own antigens being destroyed due to this, this causes an immune response

Cause abnormally low activity or over activity of the immune system.

Question 9

What factors may contribute to autoimmune aggression

Answer 9

Drugs
damage to the blood brain barrier
T and B cell deficiency

Question 10

List some examples of autoimmune diseases

Answer 10

Rheumatoid arthritis.

Type 1 diabetes

systemic lupus