Tag Archives: ttg iga

Celiac Disease: Lower TTG-IgA Titers Associated with Isolated Duodenal Bulb Presentation

Posted on by

QY Wang et al. JPGN 2025; 80:678–685. Open Access! Low TTG-IgA associated with isolated bulb pathology in pediatric celiac disease: Implications in a no-biopsy approach era

Methods: There were 405 cases included in this retrospective study (mean age = 9.6 years). TTG-IgA values were considered negative if <4 U/mL, equivocal between 4 and 10 U/mL inclusively, and positive if >10 U/mL. At the authors’ institution, TTG‐IgA ≥10× ULN corresponds to ≥100 U/mL.

Key findings:

  • Bulb-restricted CD was present in 7.4% of cases
  • TTG-IgA was negative or equivocal in 60.0% of bulb-restricted CD, compared to 5.3% of distal duodenal CD (odds ratio [OR] = 26.6
  • No bulb-restricted CD cases attained TTG-IgA ≥10× ULN, compared to 48.5% of distal duodenal CD

My take: This study confirms and quantitates what most clinicians have experienced. Isolated duodenal bulb pathology is associated with lower celiac titer abnormalities.

Related blog posts:

Gorgeous stained glass by Margaret Vetter at Piedmont Arts Festival

Is it Helpful to Check Celiac Serology Titers After 3 Months of a Gluten Free Diet?

Posted on by

A recent prospective study (D Petroff et al. Clin Gastroenterol Hepatol 2018; 16: 1442-49) with 345 pediatric patients with biopsy-proven celiac disease (CD) examined serologic response to a gluten-free diet (GFD) between 2012-2015.

Key findings:

  • Mean TTG IgA concentration decreased 14-fold after 3 months of a GFD.  The study assay used kits from EUROIMMUN.
  • TTG IgA remained above 1-fold ULN in 83.8% and above 10-fold ULN in 26.6%.
  • Deamidated gliadin IgA (DGL IgA) decreased in the vast majority but did not distinguish response of GFD from random fluctuations.
  • The authors note that symptoms improved in most on GFD, but short-term response could reflect “regression to the mean…for a considerable share” as symptoms improved in the non-GFD group as well.

In their discussion, the authors reference a large study (n=487) which showed mean normalization of TTG IgA of ~400 days; longer times were noted in those with type 1 diabetes and higher baseline values.

My take: This study, while showing that TTG IgA levels improve after 3 months of a GFD, helps solidify my opinion that in those who are improving, followup serology could be obtained later.  My practice is to have followup serology after 6 months of a GFD in the majority of patients.

Related blog posts:

Lake Moraine, Banff