Anti-tissue transglutaminase antibodies in coeliac disease are not a response to gut damage alone

BACKGROUND: Anti-tissue transglutaminase (tTG) antibody is being used increasingly as a diagnostic tool in the serological investigation of coeliac disease. However, positive predictive values of immunoglobulin A anti-tTG for coeliac disease in prospective studies have been disappointing. OBJECTIVE: To determine whether anti-tTG can arise as a non-specific consequence of abnormal gut permeability. PATIENTS: A cohort from routine investigation for possible gluten-sensitive enteropathy, with 44 cases selected based on whether permeability studies had been performed. METHODS: The cohort was assessed for anti-tTG by enzyme-linked immunosorbent assay, small-bowel biopsy and C-mannitol absorbency. RESULTS: Eighteen of the 44 patients had biopsy-proven coeliac disease and 23 showed abnormal permeability. There was poor correlation between the level of anti-tTG and gut permeability. CONCLUSIONS: These data confirm an association between anti-tTG and coeliac disease but no clear relationship with other forms of increased gut permeability.