Transcript Hypersensitivity

Hypersensitivity
Hypersensitivity reactions
• An immunological responses not controlled by
normal regulatory mechanism.
• Classification
- Gell and Coombs system
Gell and Coombs system
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•
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Type I – immediate (Ig E)
Type II – antibody mediated (ADCC)
Type III – immune complex mediated
Type IV – T cell mediated
(delay type hypersensitivity)
OUTLINE
• Hypersensitivity
-mechanism (Sensitization phase/Effect phase)
-clinical manifestation
-lab testing
Type I - immediate hypersensitivity
IgE-mediated reactions
• Mechanism :
FcεR
On mast cells
or basophils
Soluble
Antigen
Cross linking
of Fab
degranulation
Type I - immediate hypersensitivity
IgE-mediated reactions
• clinical manifestation
Atopy:
Genetically linkage
-Allergies
-Allergic rhinitis
-Asthma
-Atopic dermatitis
「濕疹」 異位性皮膚炎
-Allergic
gastoenteropathy
Lack genetic linkage
and target organ :
-Urticaria 蕁麻疹
-Anaphylaxis 全身性過敏反應
-Anaphylacic shock
Allergic rhinitis
Allergic rhinitis
Type I - immediate hypersensitivity
IgE-mediated reactions
• allergen
Host dust, arthropod, mold, weeds (ragweed), pollen,
tree, animal, food, drug, latex
Inhalant allergen
Contact allergen
Food allergen
Type I - immediate hypersensitivity
IgE-mediated reactions
• Lab test
Skin test
In vitro tests
Lymphocyte stimulation
Intranasal provocative tests
鼻內激發法
Skin test
• Cutaneous test (prick test) 扎刺法
pucture small amount to dermis and read
after 20 min
• Intradermal test 皮下過敏注射
semiquantitative
In vitro tests
體外敏感試驗
• Total IgE :
IMMULITE Total IgE (serum IgE only)
• Allergen specific IgE
RAST : radioallergosorbent test
MAST : multiple antigen simultaneous test
CAP
Immunoblot (AlaBLOT test)
--allergen: Ep strip
• Eosinophilia : 114-142  300-500/mm3
• ECP (eosinophil cationic protein)
過敏原檢測
Total IgE Test
CAP(混合過敏原群IgE抗體篩檢)
Phadiatop, fx5
or
CAP(特定過敏原IgE抗體篩檢, 自選)
MAST allergy
test
MAST(Multiple Antigen Simultaneous Test)
• 同時測定36種抗原
• 使用Chemical Luminescent ImmunoAssay
• 半定量
Allergen + tested IgE → Allergen-IgE-(Anti-IgE) → CLA-1
↑
Anti-IgE*Enzyme
• 結果判讀 : 4 : >242
3 : 143~242
2 : 66~142
1 : 27~65
±: 12~26
- : 0~11
(單位 : LUs)
＊Total IgE>500 IU/mL MAST中的
某些±可能為non-specific binding
Principle
• Chemiluminescence Analysis (化學冷光酵素免疫分析法)
Allergen + tested IgE (待測血清)
anti-IgE*enzyme
Allergy-IgE-(anti-IgE*enzyme)
photoreagent
CLA-1儀器偵測
MAST allergy test
• Introduction
─ 同時測定血清中36種過敏原的特異性IgE抗體
─ 半定量計量。結果值(LUs淨值)以級數表示
• Result
─ 分四級：0, 0/1, 1, 2, 3, 4
─ 2級以上表示有意義
• Clinical significance
─ Atopic allergy 屬第一型過敏反應。
─常見的臨床症狀有花粉熱、氣喘、皮膚炎、蕁麻疹、過敏性休克
─ 得知患者對不同過敏原的IgE濃度，是診斷和治療過敏的
重要資訊。
• MAST 36種過敏原測試
CAP
cellulose carriers
β-Galactosidase的抗IgE抗體
反應後,清洗掉未反應物,
加入反應呈色劑
於CAP機器判讀結果。
β-Galactosidase
CAP
• 吸入性混合過敏篩檢(23種)及食物性混合過
敏篩檢(6種)
CAP
• 吸入性混合過敏篩檢(23種)及食物性混合過
敏篩檢(6種)
UniCAP
UniCAP 原理: FEIA
• Fluorescence Enzyme Immunoassay (FEIA)
• Enzyme : β-galactocidase
• Substrate : 4-MUG → 4-MU
• Stop Solution : 4% Sodium Carbonate
UniCAP
• 以FEIA的方法，應用於Autoantibody(Specific IgG)和過敏免
疫系統(Total IgE, Specific IgE)的定量
• Total IgE
檢測體內所含IgE濃度，作為過敏的指標
─ 測定範圍: 2~5000 kU/L
• Specific IgE
檢測不同過敏原產生的特異性IgE抗體
─ 吸入性混合過敏篩檢(23種)及食物性混合過敏篩檢(6種)
Cyclic cirtullinared peptide(CCP) Ab
Extractable Nuclear Antigen Ab(ENA)
Eosinophil cationic protein(ECP)
將Anti-ECP固定於cellulose carriers(固相)中,
加入待測血清反應後,清洗掉未反應物,再加入
β-Galactosidase的抗ECP抗體反應後,清洗掉
未反應物,加入反應呈色劑於CAP機器判讀結果。
Anti-ECP
檢驗活化的eosinophil及其產物ECP可追蹤病程,並在
發炎期(ex.急性氣喘)給予抗發炎藥劑,降低發炎,故
檢驗血清中的ECP值是治療成效的指標。
Type I - immediate hypersensitivity
IgE-mediated reactions
Therapy
• Environmental measures : avoid allergen
• pharmacological therapies
-antihistamine
-corticosteroids
-cromolyn sodium
• Desensitization treatment
-Allergen shots (blocking antibody, IgG)
• Antibody against free and membrane IgE
• Antibody to CD23 (low affinity IgE receptor)
• Cytokine intervention
IgG
IgM
Type II – antibody mediated
• Mechanism :
Sensitization phase
1.Cell surface antigen
Transplanted cell
Host cell (autoimmune)
Foreign antigen bind to host
cells
Ag dose not clear from system
2.IgM IgG production
(dep. on cytokine)
Effect phase
1.Complement
activation
chemoattractant C5a C3a
Anaphylatoxin C5a
Opsonin
MAC
2.ADCC by NK
3.Opsonin mediated
phagocytosis
Destory
cells
IgG IgM
Type II – antibody mediated
• clinical manifestation (dep. on cell type)
-Hemolytic disease of newborn
-Transfusion reactions
-Autoimmune disorders
-Drug induced reactions
-Transplantation
Hemolytic disease of newborn
RBC-Rh antigen
Autoimmune disorder
• Goodpasture’s syndrome
Ab against kidney and lung basement membranes
Antiglomerular basement membrane antibody (Anti-GBM)
renal biopsy
even layer on the glomerular
basement membrane
• Myasthenia gravis
Ab against acetylcholine receptor in
neuromuscular junctions
down regulation of receptors by endocytosis
 muscle weakness
Drug induced reactions
ex : penicillin
Drug (hapten) Bind to cell surface
 Type II hypersensitivity
 Cell destruction
IgG
Type III-immune complex mediated
IgM
• Mechanism :
Sensitization phase
1.Chronic Ag (soluble)
exposure
autoimmue disorders
or persistent infection
2.IgM IgG production
(dep. on cytokine)
Too many immune
complexes
for phagocytes
to remove
Immune complex formation
and
deposition in the capillary walls
IgG
Type III-immune complex mediated
IgM
Effect phase
1.Complement
Anaphylatoxin
Opsonin
chemoattractant
C5a
C3b CR1
C5a C3a
2.Neutrophil
phagocytosis
damage capillary walls
(proteolytic enzyme)
3.Coagulation
Vascular permeability
PLA aggregation
 blood clot formation *
4.Immune complexes penetrate and lodged in capillary
walls
5.Vascular occlusion
Type III-immune complex mediated
• clinical manifestation
-SLE
autoantibody, immune complexes deposit in various
tissues
-Post streptococccal glomerulonephritis
S. pyogenes, kidney, “captured antigen”
-Serum sickness
passive immunization of non human IgG
human antibody – non human IgG
(ex:horse serum:anti-diphtheria antibodies,
antiserum administered following a snakebite )
-Farmer’s lung
Ag = spore of Thermophilic actnomycetes
-Arthus Reaction
Serum sickness
Arthus Reaction
• Ag inject into immunized body
• Local inflammatory response due to deposition of immune
complexes in tissues.
• vaccine boosting(第2劑)
Detection of Immune Complex
• C1q binding assay
• Raji cell assay
• Detection of Cryoglobulins
C1q binding assay
C1q binding assay
False (-)
Small immune complex、 IgE, IgA,
IgG4 immune complex
False (+)
Fibrinogen、fibronectin、DNA、
endotoxin、heparin
Raji cell assay
• Lymphoblastoid cell line from Burkitt’s lymphoma
• C1q C3b C3d and Fcg receptor
• Normal:<15.0 μgEq/mL
• positive: 20.0μg Eq/mL
Raji cell assay
• False-positives occur when
antilymphocyte antibodies are present.
• Especially in SLE, positive results often
reflect the presence of lymphocyte
antibodies.
• Raji assay are commonly found in
systemic necrotizing vasculitis and might
be useful for monitoring sarcoidosis(肉狀
瘤病).
Detection of Cryoglobulins
• Cryoglobulins are abnormal
immunoglobulins which form complexes
and precipitate out of serum at low
temperatures and resolubilise on warming.
• 4oC沉澱，加溫溶解
• responsible for specific symptoms,such as
Raynaud’s phenomenon, vascular purpura,
bleeding tendencies, cold-induced urticaria
http://www.labcorp.com/datasets/labcorp/html/chapter/mono/sc029100.htm
Detection of Cryoglobulins
Immunochemical
Composition
Type of Cryoglobulin
Type 1 : Single monoclonal
immunoglobulins
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Type II : Mixed monoclonal
immunoglobulins
• IgM-IgG
• IgG-IgG
• IgA-IgG
Type III : Mixed polyclonal
immunoglobulins
• IgM-IgG
• IgM-IgG-IgA
IgM
IgG
IgA
Monoclonal light-chains
Detection of Cryoglobulins
Type 1 : Single monoclonal •
immunoglobulins
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Myeloma
Waldenstrom’s
Chronic Lymphocytic
Type II : Mixed monoclonal •
immunoglobulins
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Myeloma
Waldenstrom’s
Macroglobulinaemia
Chronic Lymphatic Leukaemia
Type III : Mixed polyclonal
immunoglobulins
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Autoimmune Disease:
Lupus (SLE)
Rheumatoid arthritis
Scleroderma
Sjogren’s Syndrome
Chronic active hepatitis
Active Hepatitis.
Post streptococcal nephritis.
Vasculitis
Infections:
Type IV – T cell mediated
delayed-type hypersensitivity, DTH
Sensitization phase
Effect phase
Type IV – T cell mediated
macrophage activation
• clinical manifestation
chronic DTH
-Mycobacterium tuberculosis
acute DTH (24-48 hr.)
-Mantoux skin test
(PPD= purified protein derivative)
Contact
dermatitis
Mycobacterium tuberculosis
TB prevent fusion of lysosomes and
phagosomes TB live in macrophage 
macrophage destruction  chemotatic
factors release  chemotasis 聚集形成
肉芽（Tubercle，結核）
乾酪樣壞死
Type IV – T cell mediated
• Lab
patch test (read after 48 hr.):
PPD or tuberculin skin test (Koch phenomena)
Candida albicans
Streptokinase
Mumps
Trichophyton
The DTH skin test: Mantoux test
• Determine the infection of Mycobacterium
tuberculosis
(PPD= purified protein
derivative)
PPD
summary
Type I
Immediate
Type II
Ab
mediated
Type III
Immune
complex
mediated
Type IV
Cell
mediated
Soluble
Antigen
Cell
surface
Antigen
Soluble
Antigen
(many)
Effect
phase
Sensitization
phase
IgE
IgE crosslinked with
Ag
Mast cells and
basophils
degranulation
Allergies Rhinitis Asthma
Anaphylaxis Anaphylacic shock
Urticaria
Hemolytic disease of newborn
Goodpasture’s syndrome
Myasthenia gravis
Drug induced reaction
Transfusion reaction
Transplantation
SLE Post streptococccal
glomerulonephritis Serum
sickness
Persistent infection
Farmer’s lung
IgM
IgG
Ab bind to
surface Ag
*Complement
*ADCC by NK
*phagocytosis
(Opsonin)
cell destruction
IgM
IgG
Ab bind to
free Ag 
immune
complex
Immune complex
deposited in
capillary wall
localized
destruction
Naïve CD4
T cell
activation
Clinical
Macrophage
DTH
Contact sensitivity
Delay hypersensitivity
Immunity to viral and fungal
antigens and intracellular
organisms
Rejection of foreign tissue grafts
Elimination of tumor cells
bearing neoantigens
Formation of chronic granulomas
Comparison of Different Types of hypersensitivity
characteristics
type-I
(anaphylactic)
type-II
(cytotoxic)
type-III
type-IV
(immune complex) (delayed type)
antibody
IgE
IgG, IgM
IgG, IgM
None
antigen
exogenous
cell surface
soluble
tissues & organs
response time
15-30 minutes
minutes-hours
3-8 hours
48-72 hours
appearance
weal & flare
lysis and necrosis
erythema and
edema, necrosis
erythema and
induration
histology
basophils and
eosinophil
antibody and
complement
complement and
neutrophils
monocytes and
lymphocytes
transferred with
antibody
antibody
antibody
T-cells
allergic asthma,
hay fever
erythroblastosis
fetalis,
Goodpasture's
nephritis
SLE, farmer's lung
disease
tuberculin test,
poison ivy,
granuloma
examples