Immune complex disease:
  • An immunologic category of diseases evoked by the deposition of antigen- antibody in the microvasculature. Complement is frequently involved and the breakdown products of complement attract polymorphonuclear leukocytes to the site of deposition. Damage to tissue is frequently caused by the process of “frustrated” phagocytosis by polymorphonuclear cells. Vasculitis or nephritis is common. Arthus phenomenon and serum sickness are classic examples, but many other disorders, including most of the connective tissue diseases, may belong in this immunologic category; immune complex diseases can also occur during a variety of diseases of known etiology, such as subacute bacterial endocarditis. See Also: autoimmune disease. Syn: immune complex disorder, type III hypersensitivity reaction.
Serum sickness
  • Acute serum sickness is the prototype type III/immune complex mediated disease first described in 1905.
Some types of vasculitis
  • Inflammation in and around vessels causes an acute necrotizing vasculitis with fibrinoid deposition and acute inflammation (innocent bystander destruction)

graphic
Fig. 5-11 Schematic illustration of the three sequential phases in the induction of systemic type III (immune complex) hypersensitivity.
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