Aspergillus fumigatus IgA ELISA
The IMMUNOLAB Aspergillus fumigatus IgA Antibody ELISA Test Kit has been designed for the the detection and the quantitative determination of specific IgA antibodies against Aspergillus fumigatus in serum and plasma. Further applications in other body fluids are possible and can be requested from the Technical Service of IMMUNOLAB.
Aspergillus species of known pathogenicity to man are Aspergillus fumigatus, A. flavus, A. niger, A. terreus and A. nidulans. The most common pathogen of this genus is A. fumingatus which occurs in hay, grain, rotten plants and birds faeces. The main opportunistic invasive fungial infections are the candidal mycosis followed by aspergillosis. Generally infections with Aspergillus spp. are airborne. Because of the ubiquity of Aspergillus species it renders more difficult to decide between contamination by commensals or a serious infection. Usually infection in man occurs in already damaged tissues only. Aspergillus spp. can cause a chronical infection of paranasal sinus, eyes or lungs.
Three types of lung-aspergillosis can be distinguished:
a: Acute infection (bronchial pneumonia; pneumonia)
Aspergillus pneumonia is mostly found in patients with neutropenia (decrease of neutrophil granulocytes), after a long-time therapy with glucocorticoids, in immunosuppressed patients (after organ transplantation) and in alcoholics.
b: Saprophytic aspergillom (compact reticulum of hyphae in the lungs)
Preformed caves in the lung due to a previous tuberculosis give place to a colonisation of Aspergillus species.
c: Allergic bronchopulmonal aspergillosis
This clinical picture is not due to an infectious disease but a hypersensitive reaction of the bronchial system (mediated by IgE) after inhalation of aspergillus spores. Subsequently the bronchial system produces highly viscous secretions, that may block the bronchial lumen. The patient develops difficulties of breathing and a fibrosis.
Next to ELISA the indirect Aspergillus hemagglutination test (Aspergillus HAT) can be performed to detect specific IgG and IgM antibodies. The HAT is not suitable as a screening test, however, because of its low sensitivity. In some high-risk patients it shows only low antibody titers. For a better diagnosis of invasive aspergillosis the brain or lung of these patients should be examined by a biopsy.
The IMMUNOLAB Aspergillus fumigatus IgA antibody test kit is based on the principle of the enzyme immunoassay (EIA). Aspergillus antigen is bound on the surface of the microtiter strips. Diluted patient serum or ready-to-use standards are pipetted into the wells of the microtiter plate. A binding between the IgA antibodies of the serum and the immobilized Aspergillus antigen takes place. After a one hour incubation at room temperature, the plate is rinsed with diluted wash solution, in order to remove unbound material. Then ready-to-use anti-human-IgA peroxidase conjugate is added and incubated for 30 minutes. After a further washing step, the substrate (TMB) solution is pipetted and incubated for 20 minutes, inducing the development of a blue dye in the wells. The color development is terminated by the addition of a stop solution, which changes the 4 ILE-ASP02_en color from blue to yellow. The resulting dye is measured spectrophotometrically at the wavelength of 450 nm. The concentration of the IgA antibodies is directly proportional to the intensity of the color.
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