CS: Immunology Flashcards
HLA-A3
haemochromatosis
HLA-B51
Behcet’s disease
HLA-B27
ankylosing spondylitis
reactive arthritis
acute anterior uveitis
HLA-DQ2/DQ8
coeliac disease
HLA-DR2
narcolepsy
Goodpasture’s
2 sleeping in goodpastures
HLA-DR3
dermatitis herpetiformis
Sjogren’s syndrome
primary biliary cirrhosis
HLA-DR4
DM 1
RA- in particular the DRB1 gene
What are Interferons (IFN)
Interferons (IFN) are cytokines released by the body in response to viral infections and neoplasia.
DiGeorge syndrome inheritance and SX
AD, deletion of a section of chromosome 22
C - Cardiac abnormalities
A - Abnormal facies
T - Thymic aplasia
C - Cleft palate
H - Hypocalcaemia/ hypoparathyroidism
22 - Caused by chromosome 22 deletion
Hypersensitivity where:
Antigen reacts with IgE bound to mast cells
Examples
Type I - Anaphylactic
* Anaphylaxis
* Atopy (e.g. asthma, eczema and hayfever)
Hypersensitivity where:
IgG or IgM binds to antigen on cell surface
Examples (7)
Type II - Cell bound
* Autoimmune haemolytic anaemia
* ITP
* Goodpasture’s syndrome
* Pernicious anaemia
* Acute haemolytic transfusion reactions
* Rheumatic fever
* Pemphigus vulgaris / bullous pemphigoid
Hypersensitivity where:
Free antigen and antibody (IgG, IgA) combine
(3 examples)
Type III - Immune complex
Serum sickness
* SLE
* Post-streptococcal glomerulonephritis
* Extrinsic allergic alveolitis (especially acute phase)
Hypersensitivity where:
T-cell mediated (7)
Type IV - Delayed hypersensitivity
* Tuberculosis / tuberculin skin reaction
* Graft versus host disease
* Allergic contact dermatitis
* Scabies
* Extrinsic allergic alveolitis (especially chronic phase)
* MS
* GBS
hypersensitive where:
Antibodies that recognise and bind to the cell surface receptors.
This either stimulating them or blocking ligand binding
Graves’ disease
* Myasthenia gravis
Mnemonic for hypersensitivity reactions
Overview of hypersensitivity types mediators, onset
IgG
what proportion of serum antibodies?
type of molecule?
what is the role?
75%
Monomer
Enhance phaGocytosis of bacteria and viruses.
IgA
what proportion of serum antibodies?
type of molecule?
what is the role?
15%
Mono+Dimer
Found in secretions, provide localized protection on mucous membranes
IgM
what proportion of serum antibodies?
type of molecule?
what is the role?
10%
Pentamer
first to be secreted, anti-A, B blood antibodies → Blood Transfusion
IgD
what proportion of serum antibodies?
type of molecule?
what is the role?
1%
Monomer
Involved in activation of B cells
IgE
what proportion of serum antibodies?
type of molecule?
what is the role?
0.1%
Monomer
Involved in allergic reactions
Interferon/IFN-alpha
- Receptors
- produced by
- useful in 4
Interferon-alpha
- bind to type 1 receptors
- produced by leucocytes
-useful in:
—hepatitis B & C,
—Kaposi’s sarcoma,
—metastatic renal cell cancer,
—hairy cell leukaemia
flu-like symptoms and depression
Interferon/ IFN-beta
bind to
produced by
useful in (1)
bind to type 1 receptors
produced by fiBroblasts
reduces the frequency of exacerbations in patients with relapsing-remitting MS
Interferon INF -gamma
-bind to
- predominately from cells
weaker antiviral action, more of a role in immunomodulation particularly macrophage activation
INF -gamma
-type 2 receptors
-predominately NK cells & T helper cells
-weaker antiviral action, more of a role in immunomodulation particularly macrophage activation
What are Interferons (IFN)
Interferons (IFN) are cytokines released by the body in response to viral infections and neoplasia. They are classified according to cellular origin and the type of receptor they bind to
Skin prick test uses
Useful for food allergies and also pollen
Radioallergosorbent test (RAST) used for
food allergies, inhaled allergens (e.g. Pollen) and wasp/bee venom
- used when skin prick tests are not suitable, e.g. extensive eczema or if the patient is taking antihistamines
Patch testing use for
dermatitis. Around 30-40 allergens are placed on the back. Irritants may also be tested for. The patches are removed 48 hours later with the results being read by a dermatologist after a further 48 hours
What are T-helper 1 cells involved in and what do they secrete?
Th1 - involved with cell mediated response (type 4 hypersensitivity)
secrete IFN-gamma, IL-2, IL-3
What are T-helper 2 cells involved in and what do they secrete?
Th2 - involved with humoral (antibody) immunity
secrete IL 4/5/6/10/13
Complement deficiencies; what is the effect
C1 inhibitor deficiency
C3 def
C5 def
C5-9 def
C1 inh deficiency - hereditary angiodema
C3 deficiency - recurrent bacterial infections
C5 deficiency - Leiner disease (severe seborrheic dermatitis, diarrhoea, infections)
C5-9 def - encodes the membrane attack complex (MAC) prone to N.meningitidis infection
