Background: Previous studies have demonstrated that serum anti-actin antibodies are a reliable marker of intestinal damage severity in coeliac disease.
Aims: To validate in a multicentre study the clinical usefulness of serum IgA anti-actin antibody ELISA and its possible use in monitoring intestinal mucosa lesions during gluten-free diet.
Patients and methods: Four centres recruited 205 newly diagnosed coeliac disease patients with villous atrophy, 80 healthy controls and 81 "disease" controls. Twelve coeliac disease patients on gluten-free diet but with persistent symptoms underwent serum IgA anti-actin antibody assay and intestinal histology evaluation. IgA anti-actin antibody ELISA was performed with a commercial kit. All coeliac disease patients underwent intestinal histology study.
Results: IgA anti-actin antibodies showed a sensitivity of 80% and a specificity of 85% in the diagnosis of coeliac disease patients with villous atrophy. The area under the receiving operator curve for anti-actin antibodies was 0.873 [95% C.I. 0.805-0.899]. Serum anti-actin antibodies values were significantly higher in coeliac disease patients than in healthy or "disease" controls (P<0.0001). Serum anti-actin antibodies were positive in 41 of the 60 coeliac disease patients with mild intestinal histology lesions (69%) and in 123 of the 145 with severe lesions (85.3%) (P<0.05). There was a significant inverse correlation between anti-actin antibody values and the villi/crypts ratio (r=-0.423; P<0.0001). In the 12 coeliac disease patients on gluten-free diet who underwent re-evaluation as they were persistently symptomatic, intestinal histology showed three cases with persistent villous atrophy: all of these were positive for serum anti-actin antibodies ELISA, whereas both serum anti-tTG and EmAs were negative. The other nine patients showed normal intestinal villi and were negative for serum anti-actin antibodies.
Conclusions: Anti-actin antibodies are a reliable marker of severe intestinal mucosa damage in coeliac disease patients and a simple ELISA technique offers an accurate method for their determination. These antibodies seem to be a very reliable marker of persistent intestinal damage in coeliac disease patients.