Hypersensitivity is the immune system doing its job — but too hard, or against the wrong target. The Gell & Coombs scheme sorts these damaging reactions into four types by what mediates them and how fast they strike. Tap each type to see the mechanism.
Pick a type
Four ways the immune system overreactstap a type to begin
Mediator—
Onset—
Complement—
Gell & Coombs, at a glanceTypes I, II, and III are driven by antibodies; only Type IV is cell-mediated (T lymphocytes, no antibody). That single split explains why Type IV is the slow, “delayed” one.
Mnemonic — ACID:1Anaphylactic · 2Cytotoxic · 3Immune-complex · 4Delayed. First three are antibody (B-cell) work; the fourth is T-cell work.