Serum IFABP Level as an Index of Mucosal Health in Celiac Disease: A Small Intestinal Morphometry Study

To evaluate the correlation between serum intestinal fatty acid-binding protein (IFABP) levels and quantitative duodenal morphometry in adult patients with celiac disease (CeD) at diagnosis and after long-term gluten-free diet (GFD), and to assess the role of this investigation as a noninvasive marker of mucosal injury and healing.

In this prospective cross-sectional study, adult patients with CeD on a GFD for ≥18 months (follow-up [FU]) and newly diagnosed untreated patients with CeD (ND) were enrolled. Serum IFABP levels were measured by enzyme-linked immunosorbent assay (ELISA). Duodenal biopsies from FU and ND patients underwent quantitative morphometric analysis, including villous height to crypt depth (Vh:Cd) ratio, intraepithelial lymphocyte (IEL) count, and calculation of the Vh:Cd and IEL scale index. Correlation between IFABP and histological parameters was assessed.

IFABP levels were significantly higher in ND patients compared with FU ( P < 0.001). Across the cohort, IFABP levels correlated negatively with Vh:Cd ratio (ρ = -0.53, P < 0.001) and positively with IEL count (ρ = 0.46, P < 0.001). IFABP also showed a strong inverse correlation with the Vh:Cd and IEL scale index (ρ = -0.60, P < 0.001). In FU patients, IFABP remained significantly associated with subtle morphometric abnormalities, including reduced Vh:Cd ratio and increased IEL counts, but not with celiac serology or self-reported dietary adherence.

Serum IFABP levels represent a promising, noninvasive biomarker of enterocyte damage for capturing subtle changes and current mucosal status in patients with CeD on a long-term GFD, when conventional serology and dietary questionnaires may fail.