arthus definition

<person>

A French bacteriologist, 1862-1945.

See: Arthus phenomenon, Arthus reaction.

A form of immediate hypersensitivity resulting in erythema, oedema, haemorrhage, and necrosis observed in rabbits after injection of antigen to which the animal has already been sensitised and has specific IgG antibodies. The reaction is caused by the inflammation that results from the deposition of antigen-antibody complexes in tissue spaces and in blood vessel walls that activate complement, most of the damage seemingly being due to the polymorphonuclear leukocytes that phagocytise the deposits and release lysosomal enzymes. The phenomenon, described by Arthus, was in rabbits, but similar reactions (Arthus-type reactions) are observed in guinea pigs, rats, and dogs, as well as in humans.

Synonyms: Arthus reaction.

<dermatology, immunology> An inflammatory reaction due to localised injection of an antigen into an animal that has circulating IgG antibodies against that specific antigen. It is evidence of prior exposure to the antigen.

It results in immediate hypersensitivity producing erythema, oedema, haemorrhage, and necrosis and is caused by the deposition of antigen-antibody complexes in tissue spaces and in blood vessel walls that activate complement, most of the damage seemingly being due to the polymorphonuclear leukocytes that phagocytise the deposits and release lysosomal enzymes.

The phenomenon, described by Arthus, was in rabbits, but similar reactions (Arthus-type reactions) are observed in guinea pigs, rats, and dogs, as well as in humans.

See: immune complex disease, Arthus, Nicolas.

(05 Mar 2007)