What is a Type III hypersensitivity reaction?
In type III hypersensitivity reaction, an abnormal immune response is mediated by the formation of antigen-antibody aggregates called “immune complexes.” They can precipitate in various tissues such as skin, joints, vessels, or glomeruli, and trigger the classical complement pathway.
What are the manifestations of types III hypersensitive reactions?
The clinical manifestations of type III hypersensitivity reactions relate to the tissue deposition, for example vasculitic (skin), serum sickness (systemic), nephritis (kidneys) and extrinsic allergic alveolitis (lungs).
Which of the following could be the result of a Type III hypersensitivity reaction?
A unique characteristic of type III hypersensitivity is antibody excess (primarily IgG), coupled with a relatively low concentration of antigen, resulting in the formation of small immune complexes that deposit on the surface of the epithelial cells lining the inner lumen of small blood vessels or on the surfaces of …
When does type III hypersensitivity occur?
Type III hypersensitivity occurs when there is accumulation of immune complexes (antigen-antibody complexes) that have not been adequately cleared by innate immune cells, giving rise to an inflammatory response and attraction of leukocytes. Such reactions may progress to immune complex diseases.
What type of hypersensitivity is Sjogren’s Syndrome?
This is the third form of hypersensitivity in the Gell-Coombs classification, called Type III hypersensitivity. Immune complex deposition is a prominent feature of several autoimmune diseases, including systemic lupus erythematosus, cryoglobulinemia, rheumatoid arthritis, scleroderma and Sjögren’s syndrome.
What causes cell damage in a Type III hypersensitivity?
Type III, or immune-complex, reactions are characterized by tissue damage caused by the activation of complement in response to antigen-antibody (immune) complexes that are deposited in tissues. The classes of antibody involved are the same ones that participate in type II reactions—IgG…
What kind of hypersensitivity is subacute bacterial endocarditis?
Subacute bacterial endocarditis is a type of endocarditis (more specifically, infective endocarditis). Subacute bacterial endocarditis can be considered a form of type III hypersensitivity.
How long does it take for subacute endocarditis to develop?
Infective endocarditis can be either acute or subacute. Acute infective endocarditis can develop suddenly and become life-threatening within days. Subacute infective endocarditis develops slowly over a period of several weeks to several months.
When does subacute endocarditis lead to septic emboli?
Underlying structural valve disease is usually present in patients before developing subacute endocarditis, and is less likely to lead to septic emboli than is acute endocarditis, but subacute endocarditis has a relatively slow process of infection and, if left untreated, can worsen for up to one year before it is fatal.
Who was the first person to treat subacute bacterial endocarditis?
Treatment. The use of high-dose antibiotics is largely based upon animal models. Leo Loewe of Brooklyn Jewish Hospital was the first to successfully treat subacute bacterial endocarditis with penicillin. Loewe reported at the time seven cases of subacute bacterial endocarditis in 1944.
