Layer 07 · Disease
When mechanism becomes pathology
Four hypersensitivity types describe how a normal effector mechanism turns on the host. The cancer immunity cycle shows the seven steps a tumour must defeat — each one a therapeutic opportunity.
4HYPERSENSITIVITY TYPES
7CANCER CYCLE STEPS
Hypersensitivity
Same immune machinery, four different failure modes distinguished by mechanism and timing. Switch between types to compare.
Type I — Immediate (IgE)
Skin-prick, specific IgE, tryptase.Allergen cross-links IgE on mast cells/basophils → histamine, tryptase, leukotrienes within minutes.
Examples
Anaphylaxis, allergic asthma, urticaria, food allergy.
Targeted therapy
Adrenaline, antihistamines, omalizumab, allergen immunotherapy.
The cancer immunity cycle
Seven steps from antigen release to killing. Tumours escape by breaking one; immunotherapy repairs one. Walk the cycle.
Step 1 — Release of cancer antigens
How it fails
Low mutational burden; no immunogenic cell death
Therapeutic lever
Chemotherapy, radiotherapy, oncolytic viruses