14. immunopathology

Question 1

types of adaptive immunity

Answer 1

cellular and humoral

Question 2

Cell mediated immunity

Answer 2

Dependent on T lymphocytes
Ag + T cells  clonal proliferation  effector and memory T cells
Effector T cells: two main groups
Cytotoxic T cells
Helper T cells (Th1,Th2 and Th17)

Question 3

Helper/inflammatory T cells

Answer 3

Usually CD4 T cells
Specialized to activate macrophages & B lymphocytes
Three form
Th1 cell: activate macrophage to kill intracellular
organism
Th2 cell: activate B cell to make Ab
Th17 cell: recruitment of neutrophils

Question 4

th1
cytokine
ck that induces
action

Answer 4

IFN Y
INF Y IL12
macrophage avtivation

Question 5

th2
cytokine
ck that induces
action

Answer 5

IL4 IL5 IL13
IL4
IgE production against helminths

Question 6

th3
cytokine
ck that induces
action

Answer 6

IL17 IL22
TGF B IL6 IL23
RECRUIT NEUTROPHILS

Question 7

Bcell activation by 2 ways

Answer 7

t independent repetitive interaction with antigen

t cell dependent Th2

Question 8

first IgM then IgG

Question 9

antibody direct and indirect function

Answer 9

direct neutralization of virus and toxins
indirect complement activation and opsonization

Question 10

Pathology of immune system

Answer 10

Hyperfunctioning of immune system
Hypersensitivity
Autoimmune disease
Hypofunctioning of immune system(immune deficiency)
Congenital(primary)
Acquired(secondary)

Question 11

Hypersensitivity

Answer 11

Inappropriate or overreactive immune response to an antigen resulting in undesirable effects

Question 11

Four types of hypersensitivity

Answer 11

Type I (IgE-mediated)
Type II (tissue-specific)
Type III (immune complex–mediated) and
Type IV (cell-mediated)

Question 12

Type I hypersensitivity

Answer 12

= IgE-Mediated Hypersensitivity

Mast cells, basophils and eosinophils

Localized reaction: conjunctivitis, rhinitis, atopic dermatitis, hives (urticaria), hay fever, asthma and allergic gastroenteritis

Systemic reaction: anaphylactic shock (intravenous drugs, bee sting)

Question 13

local type I hypersensitivity reactions have two well-defined phases

Answer 13

immediate and late

Question 14

immediate phase

Answer 14

Occurs within minutes
of exposure to the antigen and subsides in a few hours

vasodilation
vascular leakage
smooth muscle spasm

histamine and proteases
PG D2
leukotriens B4 C4 D4

Question 15

late phase

Answer 15

leukocyte infiltration
epithelial damage
bronchospasm

Question 16

Type II: Tissue-Specific Hypersensitivity Reactions

Answer 16

= Cytolytic Hypersensitivity
IgG or IgM against a specific Ag on surface of cell or extra cellular matrix

Question 17

Mechanisms of Type II Hypersensitivity 4

Answer 17

Lysis and opsonization+phagocytosis

ADCC (antibody-dependent cellular cytotoxicity)

Complement and Fc receptor-mediated inflammation

Antibody-mediated cellular dysfunction

Question 18

Lysis and opsonization+phagocytosis

Answer 18

ag - ab
complement activation
either opsonization or cell lysis

Question 18

example of lysis and opsonization

Answer 18

Transfusion reactions,
autoimmune haemolytic anaemia,
ITP,
erythroblastosis fetalis

Question 19

ADCC (antibody-dependent cellular cytotoxicity)

Answer 19

ab - ag
recruite leukocyte
activate NK and neutrophils
phagocytosis

Question 20

example of ADCC

Answer 20

pernicous anemia

Question 21

Complement and Fc receptor-mediated inflammation

Answer 21

ab plus basement membrane ag
compliment activation
c3a and c5a chemotaxin
netrophil recritment
inflammatory cells bind to ab ag complex by fc receptor
deggranulation
tissue damage

Question 22

example of Complement and Fc receptor-mediated inflammation

Answer 22

goodpasture syndrome

rhematic fever
hyperacute transplant rejection

Question 23

Antibody-mediated cellular dysfunction

Answer 23

either block receptor so dysfunction myasthenia gravis
or
act as a ligand
graves disease

pemphigus vulgaris

Question 24

test used plus types

Answer 24

coombs test
direct detect ab on rbc surface
indirect on serum

Question 25

Type III hypersensitivity

Answer 25

= Immune complex disease
In situ or circulating antibody-antigen complexes

Sites of Deposition; Renal glomeruli , joints, skin, heart, serosa and small blood vessels.

Question 26

Antigen–antibody complexes may be 3

Answer 26

Circulating or in situ

Exogenous (eg, infectious agents and drugs) or endogenous (eg, ‘nuclear antigens’ in SLE)

Systemic (acute serum sickness) or local (Arthus reaction)

Question 27

Type III hypersensitivity 3 phases

Answer 27

ab ag complex formation

ab ag complex deposition

complement activation
either chemotaxin or anaphylaxotin

Question 28

Type IV (delayed) hypersensitivity

Answer 28

Cell-Mediated Hypersensitivity (i.e T lymphocytes)
Delayed hypersensitivity (i.e requires 24–48 hours to develop fully)

Question 29

Two types

Answer 29

Classic delayed hypersensitivity (DTH)
CD4 T cells mediate granuloma formation
PPD skin test and TB

Direct cell toxicity (cytolysis)
CD8 T cells destroy antigen-containing cells.
Contact dermatitis and graft rejection

Question 30

4 Ts for type 4 hypersensitivity

Answer 30

t cell
touch
transplant
tb

Question 31

tuberculin test

Answer 31

negative if induration is <5mm
postive if induration
>5mm for immunosuppressed

> 10mm for children

> 15mm for normal