IgA isotyping of antigliadin antibodies. A possible clue for a less invasive diagnosis of coeliac disease.
An enzyme-linked immunosorbent assay was used to measure serum antigliadin antibodies (AGA) of IgG and IgA classes. The assay was modified to measure IgA1 and IgA2 subclasses with monoclonal anti-IgA subclass antibodies. Serum IgG- and IgA-AGA levels were elevated in patients with coeliac disease (CD) but an overlap was seen with control sera. IgA-AGA isotyping using monoclonal anti-human IgA1 and IgA2 antibodies increased the sensitivity and specificity of the assay to almost 100%. All patients with active untreated CD and none of the control groups had elevated IgA1-AGA and IgA2-AGA. In order to measure the relative distribution of IgA1-AGA versus IgA2-AGA an IgA1/IgA2 ratio was calculated. In patients with active untreated CD a ratio of 2.8 was found, declining to 2.2 during treatment. A gluten challenge increased the ratio to 3.4. These findings suggest that IgA1-AGA subclass measurements are a useful screening test before small bowel biopsies are performed. This method can also be used to assess the results of a gluten free diet.
Elewaut
A
A
Department of Internal Medicine, State University of Ghent, Belgium.
Dacremont
G
G
Robberecht
E
E
Leroy
J
J
De Baets
M H
MH
D000906:Antibodies / Q000032:analysis*; D015415:Biomarkers / Q000097:blood; D002446:Celiac Disease / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D005903:Gliadin / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007132:Immunoglobulin Isotypes / Q000032:analysis*; D010940:Plant Proteins / Q000276:immunology*
D000906:Antibodies; D015415:Biomarkers; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D010940:Plant Proteins; D005903:Gliadin