From the Guidelines
The elevated anti-gliadin IgG with normal IgA, tTG, and anti-gliadin antibody suggests non-celiac gluten sensitivity (NCGS) rather than celiac disease, and a 4-6 week gluten-free diet trial is recommended to assess symptom improvement. Here's what to do:
- Recommend a 4-6 week gluten-free diet trial to see if symptoms improve, as suggested by the most recent guidelines 1.
- If symptoms resolve on a gluten-free diet, maintain this diet long-term, while monitoring for nutritional deficiencies.
- If no improvement occurs, gradually reintroduce gluten and consider other causes for symptoms.
- Do not perform a gluten challenge or intestinal biopsy, as these are not necessary for NCGS diagnosis, and may pose unnecessary risks to the patient 1. Justification: Antigliadin IgG can be elevated in NCGS, while celiac-specific antibodies (tTG, deamidated gliadin) remain normal, as noted in the guidelines for monitoring established coeliac disease in adult patients 1. NCGS is a clinical diagnosis based on symptom response to gluten elimination and reintroduction. Unlike celiac disease, NCGS does not cause intestinal damage, so invasive testing is unnecessary. A gluten-free diet is the primary treatment for symptom management in NCGS. The AGA institute medical position statement on the diagnosis and management of celiac disease also supports the use of IgA tTGA as the most efficient single serologic test for the detection of celiac disease, but notes that the additional inclusion of IgG antigliadin antibody and IgA antigliadin antibody are not warranted 1. However, the most recent guidelines from 2024 take precedence in this case 1.
From the Research
Interpretation of Elevated Anti-Gliadin IgG
Elevated anti-gliadin IgG with normal IgA, tTG, and anti-gliadin antibody can be interpreted in the following ways:
- The presence of elevated anti-gliadin IgG antibodies may indicate a gluten sensitivity or an immune response to gliadin, a protein found in wheat, barley, and rye 2, 3.
- However, the normal levels of IgA, tTG, and anti-gliadin antibody suggest that celiac disease is unlikely, as these markers are typically elevated in individuals with celiac disease 4, 5, 6.
- The sensitivity and specificity of anti-gliadin IgG antibodies for celiac disease diagnosis are lower compared to other markers such as anti-tTG and anti-endomysium antibodies 2, 5, 6.
- Elevated anti-gliadin IgG antibodies may also be seen in individuals with non-celiac gluten sensitivity, which is a condition characterized by symptoms similar to celiac disease but without the same level of immune system activation 4.
Diagnostic Considerations
The following points should be considered when interpreting elevated anti-gliadin IgG:
- A small-bowel biopsy may be necessary to confirm the diagnosis of celiac disease, as serological tests alone may not be sufficient 2, 4.
- The presence of HLA DQ2/DQ8 alleles can also be used to support a diagnosis of celiac disease, particularly in asymptomatic individuals 4.
- A gluten-free diet may be recommended to evaluate the response to gluten withdrawal and to assess the presence of non-celiac gluten sensitivity 4, 3.