Immunology Flashcards
Lactoferrin
Starves bacteria of iron
Polymorphonuclear cells
Neutrophils, eosinophils, basophils/mast cells
Monocytes/macrophages
Capable of presenting processed antigen to T cells after phagocytosis
Opsonisation
Makes more desirable for phagocytosis Pathogen covered by: Abs Complement Acute phase proteins e.g. CRP
Oxidative killing
NADPH oxidase Hydrochlorous acid
Non-oxidative killing
Bacteriocidal enzymes such as lysozyme and lactoferrin
Dendritic cells
Capable of phagocytosis Present process antigen T cells in LNs
Primary lymphoid organs
Where immune cells are developed BM: site of B cells maturation Thymus: site of T cell maturation. Involutes after puberty. Selects for low, intermediate and high affinity.
Secondary lymphoid organs
Sites of interaction between naive lymphocytes and pathogens Spleen, LNs, MALT
CD4 T helper cells
Recognise peptides presented on MHC2, extraceullar proteins Necessary for FULL B CELL RESPONSE Help CD8 T cell response
Th17
Autoimmune disease
CD8 cytotoxic T cells
MHC1 Kills cells directly: perforin (pore forming) and Fas ligand Viral infections and tumours - intracellular
B cell IgM class switching
Can isotype switch to IgG, IgA or IgE Ab
Ig Fab and Fc regions
Fab: interacts with pathogen Fc: interacts with immune system
Complement pathway
Classical pathway dependent on ACQUIRED immune response - formation of Ab-Ag complex results in change in Ab shape –> expression of binding site for C1
Mannose binding lectin pathway - not dependent on acquire immune response. Direct binding of bacterial manin
Alternative pathway - not dependent on acquired immune response. Directly tirggered by binding ofC3 to bacterial cell wall. Involves factors B, I and P
Membrane attack complex punches holes in bacterial membranes
Clinical features suggestive of immunodeficiency
SPUR
Serious
Persistent
Unusual
Recurrent
Runs in families
Oral allergy syndrome
Exposure to allergen induces allergy to food
Cross reactivity
e.g. birch pollen and rosacea fruit
Allergy
Th2 IgE type 1 hypersensitivity reaction
Majority of IgE bound to mast cells
Allergen crosslinks receptor –> release of preformed inflammatory mediators
FILLAGRIN mutation. Also defects in beta defensin predispose to staph aureus superinfection in infantile eczema. PUVA phototherapy..
Allregic march: eczema –> hay fever, asthma and food allergy
Allergy investigations
SPT: positive wheal = >2mm greater than negative control
Lab measurement of specific IgE : expensive; for patients who can’t stop anti-histamine, extensive eczema, history of anaphylxis, dermatographism
= radioimmunoassay test - RAST
Component resolved diagnostics: blood test to detect IgE to single protein components
Mast cell tryptase: biomarker for anaphylaxis. Peaks at 1-2 hours. Baseline at 6 hrs.
Anaphylaxis emergency management
IM adrenaline
Sit up
Oxygen
Fluid replacement, increase BP
Inhlaed bronchodilators
Hydrocortisone 100mg IV (prevent late phase response)
Chlorpheniramine 10 mg IV (skin rash)
Future: epipen
Contact dermatitis
Type 4 allergy
Patch test
C9 deficiency results
Latex food syndrome
T1HSR:
Some foods have latex like components
Chestnut, avocado….
Allergic rhinitis
T1HSR:
Pollern, pets, house dust mite,
Mx: ani histamine, sodium cromoglycate eye drops, steroids, ipratropium nasal spray
