Gliadin IgG Subclass Antibodies in Patients with Coeliac Disease

Abstract

We have measured IgG1, 2, 3 and 4 subclass antibodies to gliadin and casein in normal controls, treated and untreated coeliac patients. The amount of antibody in each subclass was determined separately as a titre and as a concentration, by reference to a standard curve. Both methods of quantitation, carried out in separate assays, yielded comparable results (IgG antibody r = 0.86, IgG1 antibody r = 0.89). In all the coeliac patients, the majority of antibody was IgG1, and little IgG2, 3, 4 antibody was detected. Untreated coeliac patients had higher titres of IgG and IgG1 antibodies to gliadin and casein compared with normal controls. In the treated coeliac patients compared with the normal controls, there was no significant difference between the titres of IgG and IgG1 antibodies to gliadin but there were higher titres to casein.

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

“…In terpretation of these results is difficult since neither the incidence nor the levels of gliadin-specific IgG subclasses were compared amongst the different stages of CD or with patients with other diseases. There seems to be broad agreement in the literature that antigliadin IgGl and/or IgG3 are consistently elevated in untreated CD over HC and DC, respectively [7,9,11]. No differences in gliadinspecific IgG2 and 4 levels were observed between CD and HC [7,8,11], except in one study [9] which reported lower IgG4 levels in untreated CD.…”

“…There seems to be broad agreement in the literature that antigliadin IgGl and/or IgG3 are consistently elevated in untreated CD over HC and DC, respectively [7,9,11]. No differences in gliadinspecific IgG2 and 4 levels were observed between CD and HC [7,8,11], except in one study [9] which reported lower IgG4 levels in untreated CD. Gluten exclusion in CD pa tients has been reported to cause a significant fail in anti gliadin IgGl and/or IgG3 with levels of IgG2 and 4 being unaffected [7,8].…”

“…No differences in gliadinspecific IgG2 and 4 levels were observed between CD and HC [7,8,11], except in one study [9] which reported lower IgG4 levels in untreated CD. Gluten exclusion in CD pa tients has been reported to cause a significant fail in anti gliadin IgGl and/or IgG3 with levels of IgG2 and 4 being unaffected [7,8]. Since both the duration and the degree of adherence to a GFD influences the rate and degree of reduction of total antigliadin IgA and IgG levels in CD [25,26], similar changes should also be detectable in sub class levels.…”

“…The four subclasses of IgG, termed 1, 2,3 and 4 consti tute 60-65,20-25,5-10 and 3-6% of the total IgG [6], Stud ies on the distribution of IgG subclasses directed against different dietary antigens in coeliac patients have shown that gliadin, milk, bovine and soy proteins elicit a mainly IgGl and/or lgG3 response [7][8][9]. These studies suggest that a subclass restriction specific to CD is not elicited by gliadin.…”

“…These studies suggest that a subclass restriction specific to CD is not elicited by gliadin. Previous studies have attempted to identify a char acteristic gliadin-specific IgG subclass profile capable of discriminating CD from other gastro-intestinai diseases [7][8][9][10][11]. However, no systematic comparison of these sub class patterns between healthy and disease control groups appears to have been performed.…”