Usefulness of I-FABP in the diagnosis and follow-up of celiac disease.

Title:

Usefulness of I-FABP in the diagnosis and follow-up of celiac disease.



Background:

Non-invasive tools for evaluating villous atrophy are needed to improve the diagnosis and follow-up of celiac disease (CD). Celiac antibodies are sensitive screening tools, but so far duodenal biopsies are needed to confirm the diagnosis, and no sensitive tools are available for monitoring the effect of gluten-free diet (GFD) on mucosal healing. In this respect intestinal fatty acid binding protein (I-FABP) is potentially useful since this small cytosolic enterocyte protein is released rapidly into the systemic circulation after intestinal damage.



Objective:

To determine the accuracy of a new diagnostic algorithm for celiac disease in which I-FABP levels before and after treatment combined with serologic tests and HLA typing define celiac disease in children, and to evaluate the usefulness of I-FABP for monitoring mucosal healing after gluten-free diet.



Study design:

Prospective, multicenter design. 225 children (6 months – 17 years) will be included. In all children CD screening, I-FABP levels and HLA genotyping will be determined. The routine diagnostic procedure for celiac disease will be performed; In patients with positive CD screening intestinal biopsy will be obtained. Patients with biopsy proven celiac disease and those with inconclusive biopsy will start gluten-free diet, in the latter gluten challenge will be performed after at least six months. If biopsy is normal, patients will continue gluten containing diet and will be monitored. Different from routine management is, in order to test our hypothesis, that all patients with positive CD screening, HLA riskfactors and positive I-FABP levels will start gluten-free diet, independent of duodenal histology. In all patients on gluten-free diet I-FABP levels in plasma and urine, and CD screening will be monitored for 6 months. Patients with negative CD screening will serve as controls.



Primary outcome:

The usefulness of I-FABP plasma levels for diagnosing celiac disease in children with enhanced titres of tTG, EMA and/or AGA antibodies, and genetic predisposition.



Secondary outcome:

The value of recovery of I-FABP levels in response to a gluten-free diet and the usefulness of urine I-FABP levels in diagnosing and follow-up of celiac disease.

1. The diagnosis of celiac disease can be established by positive antibody tests in combination with elevated plasma I-FABP levels that recover in response to gluten elimination without obtaining intestinal biopsies in patients with HLA risk factors;

2. I-FABP levels can be used in patient follow-up for assessment of celiac disease activity;

3. The urinary I-FABP level is a useful marker in diagnosing and follow-up of patients with celiac disease.

The moment of diagnosis and for six months after the initiation of gluten-free diet.

All children with positive celiac disease screening and elevated plasma I-FABP levels will start a gluten-free diet, independent of duodenal histology, since patients with positive celiac screening but normal biopsy are considered as latent or potential celiacs. In the latter patients a gluten challenge will be performed after at least six months of gluten-free diet.