Immunology Flashcards
What mutations results in X linked agammaglobulinaemia
Mutation in Bruton’s tyrosine kinase
Responsible for B cell maturation
Absence results in nil B cells or Ig
Susceptible for bacterial sinopulmonary infections, giardia, campylobacter, enteroviruses
What is Bruton’s tyrosine kinase
Gene responsible for B cell maturation
Absence results in nil B cells or Ig - X linked agammaglobulinaemia
What is CVID
Common Variable Immunodeficiency
Polygenic
Low IgG +/- IgM/IgA, Normal B cell count
Predisposes to sinopulmonary and GI diseases
Management of CVID
IVIg
Avoid live vaccines
Antibiotics
Mechanism of hyperIgM disease
Failure to class switch and generate memory B cells
Multiple genetic mutations but most common due to absence of CD40L on T cell (X-linked)
Predisposes to sinopulmonary and GI diseases and PCP (?CD40L plays role in T cell activation?)
Diagnostic test for specific antibody deficiency
Failure to respond to polysaccharide vaccines
Normal Ig levels, B cells present
CD4 count low, HIV negative - what is diagnosis? What needs to be ruled out?
CD4 lymphopenia (rare)
Rule out T cell lymphoma
Predisponse to T cell infections: Candidiasis, MAC, VZV, Crytococcus, PCP, viral
Rx: Infection prophylaxis
What causes chronic mucocutaneous candidiasis
Deficiency of Th17 cells
Multiple genes implicated
Recurrent candida on skin, nails, oesophagus, pulmonary, mucosa
Iron deficiency linked to what infection
Candida
Deficiency in C3 results in susceptibility to what?
Recurrent pyogenic infections
Immune complex disease
Glomerulonephritis
Breakdown of lymphocyte subsets (%)
T cells 70% (2/3 CD4, 1/3 CD8, ratio 2:1)
B cells 15%
NK cells 15%
What test is used for chronic granulomatous disease?
Neutrophil oxidative metabolism to look for neutrophil function - deficient in NADPH Oxidase
Multiple genetic mutations
describe the classical pathway for complement activation
Ag Ab complex (IgG or IgM) binds to C1 and activates it
activated C1 combines 4b and 2a via C3 convertase
feeds into terminal pathway
measure via: C1q binding assay; CH50 - measures classical and terminal pw
alternate pathway complement activation
C3 –> C3b wiht C3 convertase to form C3bBb3B; feeds into terminal pw
measure: AH50 (alternate and terminal)
Type I - Anaphylactic
- antigen reacts with IgE bound to mast cells
* anaphylaxis, atopy (e.g. asthma, eczema and hayfever)
Type II - Cell bound
- IgG or IgM binds to antigen on cell surface
- autoimmune haemolytic anaemia, ITP, Goodpasture’s, pernicious anemia, acute hemolytic transfusion reactions, rheumatic fever, bullous pemphigoid, pemphigus vulgaris
Type III - Immune complex
- free antigen and antibody (IgG, IgA) combine
- serum sickness, systemic lupus erythematosus, post-streptococcal glomerulonephritis, extrinsic allergic alveolitis (especially acute phase)
Type IV - Delayed hypersensitivity
- T cell mediated
- tuberculosis, tuberculin skin reaction, graft versus host disease, allergic contact dermatitis, scabies, extrinsic allergic alveolitis (especially chronic phase), multiple sclerosis, Guillain-Barre syndrome
Type V
- antibodies that recognise and bind to the cell surface receptors, either stimulating them or blocking ligand binding
- Graves’ disease, myasthenia gravis
acquired angioedema
> 40yo
rare
C1 inhibitor deficiency
associated with lymphomas
hereditary angioedema
mainly Dx < 20yo
C1 inhibitor deficiency (normally breaks down bradykinin)
low C4
CH50
assesses classical complement pathway
C1-9
if any one is low then total CH50 will be low
carbamazepine han chinese
HLAB 1502
allopurinol han chinese
HLA 5801
Wiskott-Aldrich syndrome
recurrent bacterial infections (e.g. Chest)
eczema
thrombocytopaenia
allergy testing
skin prick - food allergies, pollen - don’t do if hx anaphylaxis
RAST - specific IgE - use when can’t skin prick - eczema, anti histamines, anaphylaxis
skin patch - contact dermatitis
C1q deficiency
90% of people will develop SLE
have recurrent infections
Hyper IgM syndrome
defect in CD40 Ligand on activated T cells
wheat dept exercise induced anaphylaxis
specific IgE to omega 5 gliadin
