"Sera from 78 patients with GS and 80 patients with celiac disease were retrospectively assessed for immunoglobulin (Ig)G/IgA antigliadin antibodies (AGA), IgG deamidated gliadin peptide antibodies (DGP-AGA), IgA tissue transglutaminase antibodies (tTGA), and IgA endomysial antibodies (EmA)...
IgG AGA were positive in 56.4% of GS patients...
The serological pattern of GS is characterized by IgG AGA positivity in more than half of cases associated to IgA AGA in a few patients, but without EmA, tTGA, and DGP-AGA, which are the specific markers of celiac disease."
The research only compares people with symptoms (Gluten sensitivity and Celiac disease). I presume this would be a better study if they had compared the sera of people without gluten intolerance to those with GS and those with a proven celiac diagnosis.
This article does a better job at discussing IgG AGA than the first.
"There is laboratory evidence. Patients with GS are always anti-tTG-negative and EMA-negative. In 40–50% of cases, IgG-type AGA or IgA-type AGA may present, and only 50% of patients carry the HLA-DQ2 or DQ8 haplotype. That which characterizes such patients, how- ever, is that they do not show histological alterations in the small intestine upon biopsy, but at the most there is a positive increment of intrahepatic CD3 lymphocytes, albeit in a smaller amount than in CD (Marsh 0–1)."
Email me mmaloof at gmail.com if you would like my help in this sort of research or if you need any labs ordered. I am a licensed CA physician.