Immunoglobulin A (IgA) deficiency is 10 to 15 times more common in patients with celiac disease (CD) than in healthy subjects.
Serological tests have become the preferred methods of diagnosing CD in both symptomatic and asymptomatic patients.
However, commercially available serological methods are limited in that they detect only the IgA isotype of antibodies.
|All but one, IgA-deficient patients with CD were positive for IgG tissue transglutaminase antibodies.|
|Clinical and Diagnostic Laboratory Immunology|
Therefore, IgA-deficient patients with CD may yield false-negative serology.
In this study, published in Clinical and Diagnostic Laboratory Immunology, 15 pediatric patients with CD and 10 IgA-deficient pediatric patients without CD were assessed.
Patients were examined for IgA and IgG antibodies to endomysium, gliadin, and tissue transglutaminase.
The team found all 15 IgA-deficient patients with CD to be positive for endomysium antibodies of the IgG isotype, as well as for IgG gliadin antibodies.
Furthermore, all but one of the IgA-deficient patients with CD were positive for IgG tissue transglutaminase antibodies.
However, none of the IgA-deficient patients without CD were positive for any of the antibody markers.
In addition, the team found that all specimens examined were negative for IgA-specific antibodies to endomysium, gliadin, and tissue transglutaminase.
Dr Kumar's team concluded, "IgG-specific antibody tests for endomysium, gliadin, and tissue transglutaminase are useful for the identification of IgA-deficient patients with CD".
"IgG antibody tests along with tests routinely being used in clinical laboratories can reliably detect all active patients with CD".
"In addition, the levels of these CD-specific IgG antibodies could be used to monitor patient dietary compliance".