Decrease by 50% of plasma IgA tissue transglutaminase antibody concentrations within 2 months after start of gluten-free diet in children with celiac disease used as a confirming diagnostic test.

Background: Histological examination of small bowel biopsies is normally the gold standard for the diagnosis of celiac disease (CD). The objective of this study was to investigate whether the rate of decreases in elevated plasma IgA tissue transglutaminase antibody (IgA-tTG) and/or IgG deamidated gliadin peptides antibody (IgG - DGP) concentrations could be used as a confirming test for CD in children on a gluten-free diet (GFD) when biopsy was omitted in the diagnostic process.

Methods: In this retrospective study we compared children (≤18 years old) with a CD-confirming biopsy (n = 16) to children without a biopsy (n = 18). After initiation of GFD the antibody half-life (the time (T½) when the antibody concentration is 50% decreased) was determined in all children.

Results: Children with a biopsy (IgA-tTG, T½ = 1.9 months; IgG - DGP, T½ = 2.2 months) and children without a biopsy (IgA-tTG, T½ = 1.6 months; IgG - DGP, T½ = 2.7 months) had comparable T½ (mean) results (p < 0.05) supporting that all children had the CD diagnosis.

Conclusions: When biopsy was omitted a rapid rate of decrease in CD antibody concentrations confirmed the CD diagnosis in children on GFD. The half-lives (T½) of IgA-tTG were less than 2 months in CD children.