Celiac.com 07/01/2009 - Immunity to food allergens such as gliadin, or the proteins in cow's milk is central to prevention of certain diseases via an appropriate restriction diet. Detecting heightened levels immune reactions to antigen(s) in food is important because scientists have credible reports of certain health disturbances, such as celiac disease, and some pre-malignant conditions, such as monoclonal gammopathy of undetermined significance (MGUS), disappearing under a regimen of appropriate food restriction diets.

Only a small number of genetically predisposed individuals show a toxic  small bowel mucosa reaction to gliadin. Since levels of immunogenic gliadin may vary between different wheat species, a team of researchers first set out to assess immunogenic gliadin levels in ten bread wheat types and in three strains of commercially grown durum wheat.

The team was made up of Aleksandra Konic-Ristic, Dejan Dodig, Radmilo Krstic, Svetislav Jelic, Ivan Stankovic, Aleksandra Ninkovic, Jelena Radic, Irina Besu, Branka Bonaci-Nikolic, Njegica Jojic, Milica Djordjevic, Dragan Popovic, and Zorica Juranic.

They were spurred by previous studies that showed sera of some of multiple myeloma (MM) patients with elevated levels of anti-gliadin IgA, without enhanced levels of anti-gliadin IgG antibodies, as determined by commercial ELISA test.

They designed their own specifically to uncover any hidden anti-gliadin IgG immunoreactivity in patient blood samples. For this reason, researchers tested blood of both MM patients and celiac disease patient for immunoreaction with native gliadin isolated from regional wheat species used for bread and pasta making.

The team isolated gliadin from wheat flour by two step 60% ehanolic extraction. They determined gliadin levels by commercial R5 Mendez Elisa using PWG gliadin as the standard.

Results showed immunogenic gliadin content varies between 50.4 and 65.4 mg/g in bread wheat samples and between 20 and 25.6 mg/g in durum wheat samples.

Anti-gliadin IgA and IgG immunoreactivity of patients'sera in (IU/ml) was first measured by commercial diagnostic Binding Site ELISA test, and then additionally by non-commercial ELISA tests, using standardized ethanol wheat extracts -gliadin as the antigen.

In both patient groups, IgA immunoreactivity to gliadin from different samples was almost homogenous and in correlation with results from commercial test, except for one IgA(lambda) myeloma patient. However, results for IgG immunoreactivity were less homogeneous.

Results showed different immunogenic gliadin epitope levels in various species of wheat. They also point to a need for developing a new standard antigen, a representative mixture of gliadin isolated from local wheat species used for bread production in corresponding geographic region for ELISA diagnostic tests.

Source:
BMC Immunology 2009, 10:32
 

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