Differentiation of Coeliac Disease and Other Malabsorption Diseases Using Specific Serum Antigliadin IgG Subclass Profiles and IgA1 Levels

Abstract

The differential diagnostic potential of serum gliadin-specific IgG subclass antibodies was assessed by comparing the antigliadin IgG1, 2,3,4 profile at different stages of coeliac disease with that of gastro-intestinal infection and also conditions associated with increased intestinal permeability. The IgG subclass profile of untreated coeliac disease was found to be the same as in healthy controls (IgG1 ≈ IgG2 > IgG3 > IgG4), with only the magnitude of the individual subclass responses being increased in coeliac patients. Coeliac adults and children on gluten-free diets had different antigliadin IgG subclass profiles with IgG2 being elevated. Increased intestinal permeability or recent gastro-intestinal infection did not alter the antigliadin subclass profile from that observed in healthy individuals. Assessment of the diagnostic potential of antigliadin IgA1 and IgG1–4 measurements in screening for coeliac disease demonstrated that measurement of subclasses of gliadin-specific IgA and IgG was less sensitive and specific compared with the combined use of total antigliadin IgA and IgG. Therefore it is suggested that IgG subclasses should not be used for routine screening for coeliac disease.