Expansion
Cell-derived mediators such as histamine, and plasma-derived cascades
Expansion
Cell derived
- Histamine: mast cells, basophils, platelets. Immediate vasodilatation and permeability
- Serotonin: platelets
- Prostaglandins: vasodilatation, pain, fever
- Leukotrienes: bronchoconstriction, permeability, chemotaxis (LTB4)
- Platelet activating factor
- Cytokines: IL-1, IL-6, TNF-alpha driving the acute phase response and fever
- Chemokines: IL-8 for neutrophil chemotaxis
- Nitric oxide, free radicals, lysosomal enzymes
Plasma derived (four interlocking cascades, all initiated by factor XII)
- Complement: C3a and C5a are anaphylatoxins, C5a is chemotactic, C3b opsonises, C5-9 lyses
- Kinin: bradykinin, causing pain and permeability
- Coagulation and fibrinolytic systems
Chemotactic agents worth grouping: C5a, LTB4, IL-8 and bacterial peptides.
Drug targets map onto this list, which is why the same mediator list explains the action of aspirin, montelukast, antihistamines, corticosteroids, anti-TNF and anti-IL-6 biologics, and C1 esterase inhibitor concentrate in hereditary angioedema.