Classification for Hypersensitivity Reactions

Term

Key Factor

Type

immediate

IgE and mast cell degranulation

I

antibody-mediated

IgM and IgG antibodies to fixed antigen, complement binding with cytolysis

II

immune complex

circulating antigen which binds antibodies and complement, deposited in vessel walls with vasculitis

III

delayed, cell-mediated

T-cells with cytokine release, natural killer cells

IV

Type

Example

I

allergy

II

immune hemolysis

III

serum sickness

IV

reaction to PPD