Hypersensitivity and autoimmune

Question 1

How does type 1 hypersensitivity arise

Answer 1

inappropriate synthesis of IgE antibodies

Question 2

What is an atopy

Answer 2

genetic tendency to produce IgE to common allergens

Question 3

What are the steps type 1 hypersensitivity

Answer 3

Allergen is taken up by antigen presenting cell (macrophage) which MCH2 epidote informs Th2 helper cells of allergens presence, which stimulated B cells to produce IgE antibodies, bind to mast cells and release inflammatory mediators (histamine and prostaglandins)

Question 4

What is produced from mast cells in early phase allergic reactions

Answer 4

Histamine

Question 5

What happens in late phase allergic reactions

Answer 5

Newly synthesised prostaglandins

and T helper cells cause cytokines

Question 6

What antibodies mediate type 2 hypersensitivity

Answer 6

IgG and IgM

Question 7

What happens in type 2 sensitivity

Answer 7

targets self antigens and causes tissue damage by Fc binding to IgM or IgG

Question 8

What is antibody-dependent cell-mediated cytotoxicity

Answer 8

lyses of a target cell, whose membrane-surface antigens have been bound by specific antibodies.

Question 9

How does tissue damage occur in type 2 hypersensitivity

Answer 9

Complement lysis
Fc biding stimulating phagocytosis
antibody-dependent cell-mediated cytotoxicity

Question 10

What occurs in type 3 hypersensitivity

Answer 10

Results due to abnormal decomposition of immune complexes, as the immune complex formed for transport pathologically deposits into the tissues and causes inflammation

Question 11

What is localised pathological immune complex activation

Answer 11

ARTHUS REACTION immune complexes deposited in local tissue

Question 12

What is a systemic pathological immune complex activation

Answer 12

SERUM SICKNESS immune complexes deposited in many tissues

Question 13

What is an immune complex formation

Answer 13

degraded antibodies, gaining access to bloodstream in soluble complex and transported to liver and spleen for phagocytes to destroy the complex

Question 14

Which type of hypersensitivity is delayed

Answer 14

Type 4

Question 15

What is type 4 hypersensitivity mediated by

Answer 15

Th1 Cells and cytokines

Question 16

What occurs in type 4 hypersensitivity

Answer 16

Immune system finds it difficult to destroy environmental factors (that have no adverse effect) detected by antigen presenting cell, Th1 cells therefore overreacts producing cytokines, stimulating inflammation

Question 17

What do you call environmental factors of low molecular weight and what do they combine with

Answer 17

Haptens

Endogenous Carrier proteins

Question 18

What is autoimmunity

Answer 18

failure to recognise self and non self due to the breakdown of tolerance

Question 19

Define tolerance

Answer 19

The immune systems ability to recognise self antigens

Question 20

What are the two types of tolerances

Answer 20

Central

Peripheral (escaped central tolerance)

Question 21

What factors induce autoimmunity

Answer 21

Genetic factors 
Immune regulatory factors
Hormonal factors
Environmental factors 
Trauma

Question 22

What are the effector mechanisms in involved in autoimmune disease

Answer 22

Cellular mediated T cell
Antibody mediated B cell
Antibody + complement
Immune complex mediated (type 3 hypersensitivity)
Recruitment of innate components (phagocytes, cytokines)

Question 23

What are the sequence of basic events in autoimmunity

Answer 23

Initiating event 
Genetic factors 
Breakdown of self tolerance 
auto reactivity 
Humoral or cellular 
Tissue damage

Question 24

What is the spectrum of autoimmune disorders

Answer 24

Organ specific (Endocrine) to Non Organ specific (connective tissue)

Question 25

In type 4 what are the cytosine products

Answer 25

interlukin 2

gamma interferon