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Arthus reactions (type III hypersensitivity reactions) are rarely reported after vaccination and can occur after tetanus toxoid–containing or diphtheria toxoid–containing vaccines. An Arthus reaction is a local vasculitis associated with deposition of immune complexes and activation of complement.
Serum sickness is a type III hypersensitivity reaction, caused by immune complexes. [2] When an antiserum is given, the human immune system can mistake the proteins present for harmful antigens . The body produces antibodies, which combine with these proteins to form immune complexes. [ 2 ]
The mechanism by which immune complexes are pathogenic is complex and much of what we know is derived from experimental models of the Arthus reaction and serum sickness. These models support that Fc receptors play a dominant role in the response which can be augmented by the complement system via the anaphylatoxin C5a.
The immune reactions are usually referred to as an over-reaction of the immune system and they are often damaging and uncomfortable. [ 4 ] In 1963, Philip George Houthem Gell and Robin Coombs introduced a systematic classification of the different types of hypersensitivity based on the types of antigens and immune responses involved. [ 5 ]
Laboratory abnormalities include normal or mild decreases in serum C3, C4, and CH50 levels, and mild proteinuria. In contrast to true serum sickness, renal and hepatic involvement is rare. Significant decreases in serum C3, C4, and CH50, reported in the literature for true serum sickness, are rarely described in serum sickness–like reaction.
Nicolas Maurice Arthus (/ ɑːr ˈ tj uː s /, 9 January 1862 – 24 February 1945) was a French immunologist and physiologist. The Arthus reaction, a localized inflammatory response, is named after him. Arthus was born on 9 January 1862 in Angers, France. He studied medicine in Paris and received his doctorate in 1886.
Hypersensitivity Pneumonitis; Other names: Allergic alveolitis, bagpipe lung, extrinsic allergic alveolitis (EAA) High magnification photomicrograph of a lung biopsy taken showing chronic hypersensitivity pneumonitis (), showing mild thickening of the walls of the small air sacs by invasion of white blood cells.
Type IV hypersensitivity, in the Gell and Coombs classification of allergic reactions, often called delayed-type hypersensitivity, is a type of hypersensitivity reaction that can take a day or more to develop. [1] Unlike the other types, it is not humoral (not antibody-mediated) but rather is a type of cell-mediated response.