Determination of anti-deamidated gliadin/anti-tissue transglutaminase antibodies in patients with anti-gliadin and anti-cow's milk antibodies

Abstract

Celiac disease (CD) is autoimmune enteropathy caused by high gluten sensitivity of affected individuals. The most common manifestations are chronic diarrhoea, fatigue, anemia, weight loss and others.

Serological tests comprise determination of anti-tissue transglutaminase (atTG-IgA,IgG), anti-endomysial (IgA,IgG-EMA,EMG), anti-gliadin (IgA,IgG-aGA,aGG) and anti-deamidated gliadin/anti-deaminated gliadin peptides (IgA,IgG-aDGA,aDGG) antibodies. Since aDGA and aDGG tests have been shown to have higher sensitivity and specificity as aGA and aGG, they can be used in case where aGG and/or aGA is elevated for reasons other than CD.

Another disease with symptoms similar to those of CD is cow´s milk intolerance with presence of anti-cow´s milk IgG and/or IgA antibodies (aCMG,aCMA). Presence of both aG and aCM is not uncommon and is probably the result of increased permeability of gut´s mucosa inflammation.

Determination of aDG antibodies could be an useful tool to distinguish between CD and non-CD states (e.g.cow´s milk intolerance), since its better performance than aG tests that is even comparable to atTG antibodies assay. In addition, as a IgG+IgA screening test, its cost is remarkably lower that the usual atTG IgA and EMA (often + aGG, aGA) combination.

Even better performance can be achieved with aDG+atTG IgG+IgA screening test. In this work a group of 50 patients with various immunological disorders different from CD with aGG/A and aCMG/A both present was tested for aDGG+A and aDG+atTG IgG+IgA antibodies (ELISA).

Both screening tests were negative in more than 80 % of cases. Therefore, CD could be exluded as the probable diagnosis on the basis of these screening tests without the need of further testing for atTG and EMA antibodies.