Lesson 12 Immune Flashcards
Hypersensitivity 1-3
Allergy
Autoimmunity
Alloimmunity
Allergy definition
Allergy is a harmful effects of hypersensitivity to environmental antigens
Autoimmunity definition
Intolerance to self-antigens and attacks
Alloimmunity
Immune reaction to tissues of other individuals (transplant 器官移植）
Allergy allergen
有咩allergen？
Environmental
Atypical（非正常）
Genetic predisposed （遺傳傾向）
Allergen is too big to be phagocytosed
Or coated with non-allergenic
Allergen eg pollen, egg, fish, cigarette, animal, drug like penicillin
Allergy type 1-4
Type 1: IgE mediated( immediate response)
Type 2: tissue specific reaction
Type 3: immune complex mediated 免疫 複合
Type 4: cell mediated( delayed)
Type 1 allergy
IgE bind to mast cell
Allergic symptoms in immediate hypersensitivity reactins
Histamine
Acting on H1 receptors: contracts bronchial smooth muscle
-) bronchial constriction -) increased permeability-) erythrocytes increase-) increase blood flow
Acting thru h2 receptors
Gastric acid secretion control
Hypersensitivity process
Antigen bind to antibody
To cardiovascular -) vasodilation -) low blood pressure, faint
To skin-) nerve end irritation -) itching skin
To lung-) constriction of bronchioles-) airway obstructed-) dyspnea
ALL: SEVERE OXYGEN DEFICIT TO BRAIN
Type 1 hypersensitive manifestation (IgE)
Itching
Hypotensiion
Bronchospasm
Dysrhythmias
Such as clinical asthma, anaphylaxis
Treatment for type 1 hypersensitivity
Genetic predisposition
Test: food challenge, skin test, lab test
Desensitisation
Type 2 hypersensitivity (tissue specific mediate)
5 mechanisms+ clinical malfunction
- Cell is destroyed by antibodies and complement
- Cell destruction through phagocytosis
- Soluble antigen may enter the circulation and deposit on tissue.
- Antibody-dependent cell-mediated cytotoxicity
- Cause target cell malfunction
Clinical example
Autoimmune haemolytic anemia
Attack RBC
Blood type against
Type A against B
Type B against A
Type AB no against
Type O both against
Type 3 immune complex mediate
Antigen-antibody complex
Large-) macrophage
Small-) renal clea rance
Intermediate中型 -) deposit in tissue
Type 3 example? (Antigen-antibody)
Systemic lupus erythematosus
Rheumatoid arthritis
Antibody vs antigen
- Antibody binds to antigen
2.immune complex form in circulation - Complex deposit in blood vessel
- Activated complement
- Inflammatory response
6.release chemical mediator - Tissue damage
Type 4 hypersensitivity (not involved antibody)
Any example?
Two types, what?
Transplant reaction( graft injection. 排斥植入物）
A. Direct cell mediated
Kill the target cell by cytotoxity
B. Delayed-type hypersensitivity
Later kill
4 type of inflammation summary
Type 1
Eg: hay fever, anaphylax
Mechanisms: IgE bond to mast cell, release histamines
Effect: immediate inflammatory response
Type 2:
Eg: ABO blood incompatibility
Mechanism: IgG/ IgM react
Effects: cell lysis, phagocytosis
Type3
Eg: glomerulonephritis
Mechanism: antigen-antibody complex
Effects: inflammation
Type4
Eg: Contact dermatitis
Mechanism: antigen binds to T cell, lymphocytes kill them
Effects: immediate/ delayed inflammation
Autoimmunity
Definition
Immune system cannot distinguish self and non-self
1. Breakdown of tolerance
2. Hidden antigen
3. Infectious diseases-molecular mimicry(扮
4. Neoantigen
Systemic lupus erythematosus 紅斑狼瘡
Chronic multisystem inflammation
1. Presenting large area of circulating autoantibodies against DNA, platelets, erythrocytes
2. Immune complex deposited in connective tissue
Activate complement, causing inflammation
Clinical manifestations of systemic lupus erythematosus
Arthritis,
Rash
Renal disease
Hematological change
Joints: polyarthritis
Skin: butterfly rash
Kidney: glomerulonephritis with immune-complex deposit in glomerular
Lungs: pleural inflammation, causing chest pain
Heart: carditis, any layer of heart’s inflammation
Blood vessels: periodic vasospasm
CNS: Psychoses
Bone marrow: anemia, leukopenia, thrombocytopenia
Alloimmunity
Definition
React with antigens on tissue of other genetically dissimilar members of same species
( transplant rejection)
Graft rejection mechanism
Type 4 cell mediated!!!!
Human leukocyte antigens
- Hyperacute:
Immediate and rare, have preexisting antibody to the antigen. - Acute: cell-mediated immune response against unmatched HLA antigen
- Chrinic:
Take months or years
Inflammatory damage to endothelial cell of vessel due to a weak cell-mediated reaction against minor HLA antigens
Transfusion reaction(血
S/s of transfusion reaction
- Agglutination 凝集
Antigen-antibody reaction occurs when blood group not matched-) blood cells form a clump
s/s
Early sign: fever, hypotension, flushing, wheezing, anxiety, red urine
Late sign: generalized bleeding tendency全身出血, hypotension
Immune deficiency
Immune system fsil to self-defense
Congestions（genetic abnormality)一-） Aquired immune deficiency.(cause by illness, cancer, viral infection, aging.
.
Cause of immune deficiency+ clinical manifestations
- Disruption of T cell function
- Deficiency caused by emotional stress
- Prevent matural of stem cell into B or T
Clinical manifestations:
1. Development of unusual, severe infections.
2. T cell deficiency
3. B cell and phagocytes deficiency
4. Complement deficiency
