hypersensitivity Flashcards
classification of hypersensitivity:
Type I – hypersensitivity ( === )
Type II — mediated cytotoxicity
Type III Immune — deposition
Type IV — hypersensitivty ( — )
immediate IgE
antibody
immune complex
delayed ( cellular )
Rhinitis
Asthma
Urticaria
Angioedema
Anaphylaxis
(Eczema – mostly cellular response)
are all examples of –
IgE mediated disease ( atopic disease)
— is a potent immunological reaction, leading to tissue damage. Often (incorrectly) used interchangeably with allergy
- its seen in — disease, — , and other –
hypersensitivity
autoimmune allergy n immunopathology
phases of IgE response:
— - asymptomatic
—- of response
— of response
sesnistation
early/acute
late phase
- sensitisation precedes allergic reaction:
-Sensitisation can occur on – or — exposure
-Some patients tolerate penicillin for decades, and then develop allergy in old age
-You can be sensitised by substance itself, or something which
crossreacts with it eg Pholcodine & rocuronium - u can use — test for allergen specific IgE
- immediate reaction when it reads at–
- delayed reaction takes —
first or subsequent
skin prick test
15 minutes
several hours / next day
mechanism of tissue injury ii :
Type ii Hypersensitivity aka –
— binds to – component
— is activated
Influx of — cells lead to tissue –
Autoimmune cytopenias, – disease
ii Antibody mediated cytotoxicity
antibody binds to tissue
complement
inflammatory cells
damage
anti-GBM
in type ii hypersensitivity indued by exogenous agents:
drugs/metabolite will be — and then bypasses the — by which – will be produced lysis for RBC/ platelets and phagocytosis
absorbed
self tolerate
antibody
1- special type ii hypersneitivty:
Antibodies may bind to functionally important — .
Can — the receptor – inhibitory effect
Can have an — effect
2- blocking antibodies:
- such as —
- antibody to — receptor on the motor end plate
motor nerve cant — muscle to contract
3- agonist effect:
- such as —
- form of —
- also nonthyroid effects as —
- antibody binds to —
- constant —
- thyroxine –
receptors
block
agonist
myasthenia gravis
acetylcholine
signal
graves
hyperthyroidism
exophthalmos
TSH-receptor
constant agonist
overproduced
1-novel mechanisms:
ANCA – activate –
Anti-cardiolipin antibodies –
contribute to — effects
2- libratory tests - type ii hs:
-Tissue specific antibodies
— : – almost 100% sensitive
- Many other diseases – less sensitive
-Complement consumption often – – see on – ; don’t see consumption in –
-Immunoglobulin deposition on biopsy
neutrophils
thrombotic
GBM
masked
biopsy
serum
1- mechanism of tissue injury iii:
- Type III Hypersensitivity aka –
-Antibody binds to – (soluble or in tissue)
- — is activated
- If not cleared, may get lodged in tissue
- as : — , —
- classical Arthur reaction is a – type iii hs
2- lab test includes:
- — studies
C3 & C4 (low levels in serum due to consumption)
-Common Causes as:
— Disease
Anti-nuclear antibody/ Connective Tissue screen
(Anti-dsDNA, anti-ENA)
Rheumatoid disease - — ; —
Immune complex deposition
antigen
complement
SLE + Rheumatoid vasculitis.
localised
complement
connective tissue disease
RF + anti ccp
mechanism of tissue injury iv:
-Type IV Hypersensitivity aka –
- Antigen presented to –
-T cell activated & secretes –
-Macrophages activated by –
- As: — , contact – , Severe Cutaneous Adverse reactions (SCARs) these include toxic epidermal necrolysis, DRESS. ( drug reaction w estionphilia and systemic symptoms ) and AGEP ( acute genreliased exanthematous pustlulois )
delayed
t cells
chemokine
interferon
RA , dermatitis
we can use matoux and head test
immune responses in health n disease:
mechanism : role in protection : allergy: autoimmunity
1- IgE ( type I hs) for — and multicellular — : allergy is — : autoimmune is none proven possible CSUA
2- antibody biding to target (type ii) role in — and allergy includes drug induced — and autoimmunity is —
3-immune complex formation type iii role in — of toxins , allergy is — and – sickness and autoimmunity is — , —
4- delayed hypersensitive is type iv which has a tole in containment of — and – infections , allergy as — and — and autoimmunity as —
hemonith + parasite
anaphtlix
opsonisation
haemolytic anemia
goodpasture syndrom
neutralisation
arthus reaction and serum sickness
systemic lupus and erythematous
mycobacterial infection and viral infection
dermatitis and SCAR
RA
allergic asthma is —-
anti gbm disease is —
systemic lupus erthrymous SLE ad systemic immune complex disease and some pneumonitis is —-
some hypersensitivity pneumonitis and scarodosis is —
type I aka ige mediated
type ii
type iii
type iv
( not all allergy is IgE mediated and the same immune mechanisms which protect us, can cause tissue injury when inappropriately triggered and hs is used ad a classification scheme )
