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Flashcards in Hypersensitivity and autoimmune Deck (25)
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1

How does type 1 hypersensitivity arise

inappropriate synthesis of IgE antibodies

2

What is an atopy

genetic tendency to produce IgE to common allergens

3

What are the steps type 1 hypersensitivity

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)

4

What is produced from mast cells in early phase allergic reactions

Histamine

5

What happens in late phase allergic reactions

Newly synthesised prostaglandins
and T helper cells cause cytokines

6

What antibodies mediate type 2 hypersensitivity

IgG and IgM

7

What happens in type 2 sensitivity

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

8

What is antibody-dependent cell-mediated cytotoxicity

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

9

How does tissue damage occur in type 2 hypersensitivity

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

10

What occurs in type 3 hypersensitivity

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

11

What is localised pathological immune complex activation

ARTHUS REACTION immune complexes deposited in local tissue

12

What is a systemic pathological immune complex activation

SERUM SICKNESS immune complexes deposited in many tissues

13

What is an immune complex formation

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

14

Which type of hypersensitivity is delayed

Type 4

15

What is type 4 hypersensitivity mediated by

Th1 Cells and cytokines

16

What occurs in type 4 hypersensitivity

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

17

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

Haptens
Endogenous Carrier proteins

18

What is autoimmunity

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

19

Define tolerance

The immune systems ability to recognise self antigens

20

What are the two types of tolerances

Central
Peripheral (escaped central tolerance)

21

What factors induce autoimmunity

Genetic factors
Immune regulatory factors
Hormonal factors
Environmental factors
Trauma

22

What are the effector mechanisms in involved in autoimmune disease

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

23

What are the sequence of basic events in autoimmunity

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

24

What is the spectrum of autoimmune disorders

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

25

In type 4 what are the cytosine products

interlukin 2
gamma interferon

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