Sugar tests detect celiac disease among first-degree relatives.

OBJECTIVES: First-degree relatives of patients with celiac disease are at high risk for developing the disease themselves. Detection of serum antibodies and intestinal permeability tests have been useful to identify candidates for intestinal biopsies. Recently it was demonstrated that abnormal sucrose permeability is a very sensitive marker of active disease. Our objectives in this prospective study were (1) to assess the screening value of permeability tests, and (2) to compare the usefulness of these markers with that of the celiac disease-related serology in screening for celiac disease in a cohort of first-degree relatives of well-known patients. METHODS: We performed sugar tests in 66 first-degree relatives of probands. Subjects ingested 450 ml of a solution containing sucrose (100 g), lactulose (5 g), and mannitol (2 g). Subsequently, a complete overnight urine collection was obtained. Measurement of sugars was performed by high-performance liquid chromatography. All relatives were evaluated for antigliadin (type IgA and IgG) and endomysial antibodies and subjects positive for any test underwent intestinal biopsy. RESULTS: Twelve relatives were diagnosed as having small intestinal mucosal atrophy. Increased sucrose permeability was detected in 9 (75%) of these patients. Four false-positive determinations were found but all had gastric erosions, which is known to increase sucrose permeability independently of duodenal damage. Increased lactulose/mannitol ratios were observed in all new celiac patients. An additional nine relatives had positive results; however, four of them did not accept intestinal biopsy and the remaining five did not seem to have histological evidence of disease. Endomysial antibodies were detected in 11 of 12 patients and no false-positive cases were observed. Antigliadin antibodies were 75% sensitive and 88% specific. CONCLUSIONS: Our study demonstrated that screening using the endomysial antibody test is highly sensitive and specific for detecting celiac disease; however, almost 10% can be missed. The addition of lactulose/mannitol permeability testing to the screening protocol allowed us to detect all relatives who actually presented with evidence of gluten sensitivity. Sucrose permeability exhibited a lower sensitivity; however, it did detect other endoscopically visible lesions.