A recent cross-sectional study (K Gerasimidis et al. JPGN 2018; 67: 356-60) examined the use of fecal gluten immunogenic peptide (GIP) to assess for adherence with gluten free diet (GFD) in biopsy-proven celiac disease (CD).
GIP reflects recent gluten consumption. There is a commercially-available kit available (Ivydal GIP Testing) –though I am uncertain about how its reliability compares to the GIP measured in this study.
In the study, the authors note that GIP positivity can occur with as little as 100 mg of gluten/day ingestion. GIP is a 33-mer peptide from α2-gliadin that is stable against breakdown by gastric, pancreatic, and intestinal brush border enzymes.
Key findings of this study:
- GIP was detectable in 16% of patients with previous CD diagnosis (N=67)
- GIP was detectable in 95% of newly-diagnosed CD patients (n=19) and was detectable in 27% at 1 year afterwards.
- When compared with traditional indicators of GFD adherence (eg. TTG levels, Biagi score, clinical assessment), 4 out of 5 children with detectable GIP were missed
My take: Fecal GIP for celiac disease adherence has similar potential as a biomarker as calprotectin has for IBD. A normal GIP appears to be much more sensitive at detecting gluten ingestion.
Related blog posts:
- Followup biopsies in Pediatric Celiac disease?
- Are followup biopsies necessary for Celiac disease? Look beyond the headlines
- Closer followup for Celiac disease & pediatric guidelines
- How Accurate is Serology at Predicting Mucosal Healing in Pediatric Celiac Disease?
- Expert review: Celiac disease
- Never Too Old for Celiac Disease