Arthus reaction (redirected from Arthus reactions)

Arthus reaction

[ärto̅o̅s′]

Etymology: Nicholas M. Arthus, French physiologist, 1862-1945

a rare, severe, immediate nonatopic hypersensitivity reaction to the injection of a foreign substance, that usually is not irritating but in certain individuals is antigenic. The reaction is thought to involve the formation of an antigen-antibody complex that activates complement. Acute local inflammation, usually in the skin and marked by edema, hemorrhage, and necrosis, occurs at the site of injection. Also called Arthus phenomenon. See also serum sickness.

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Arthus reaction

a local antibody-mediated hypersensitivity reaction in which antibody-antigen complexes which fix complement are deposited in the walls of small vessels causing acute inflammation with an infiltration of neutrophils. Characteristic of type III hypersensitivity reactions. See also serum sickness.

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passive cutaneous Arthus reaction

antiserum is injected intravenously and the corresponding antigen is injected into the skin.

reverse passive Arthus reaction

antiserum is injected into the skin and the antigen is injected into the same site or intravenously.

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immune complex disease

Immunology Any of a number of conditions—caused by circulating antigen-antibody-immune complexes, which in the face of mild antigen excess, lodge in small vessels and filtering organs of the circulation Clinical Fever, enlarged and/or tender joints, splenic congestion, proteinuria due to glomerular IC deposition, eosinophilia, hypocomplementemia, lymphadenopathy, glomerulonephritis–HTN, oliguria, hematuria, edema, skin–purpura, urticaria, ulcers, carditis, hepatitis, myositis, necrotizing vasculitis. See Immune complex.

Immune complex disease

Arthus reaction Acute hemorrhagic necrosis that follows re-exposure to an antigen, which attracts PMNs, activates complement, binds ICs by the Fc receptor, causing phagocytosis, ↑ production of chemotactic factors, especially C5b67 and ↑ anaphylotoxins C3a and C5a, resulting in vasodilation

Serum sickness A reaction that is milder than the Arthus reaction, occurring 8-12 days after exposure to the antigen, at the time of 'equivalence' (antigen and antibody are in a 1:1 ratio), after injection of a foreign protein mixture, eg horse serum for antitoxin to tetanus