Letter: nonresponsive coeliac disease and evaluation of the strictness of a gluten-free diet - authors' reply.

Abstract

We thank Professor Matuchansky for his comments concerning our manuscript.1, 2 Continued gluten ingestion is surely the leading cause of nonresponsive coeliac disease. Similar to our patient series, some patients suffering from type 1 or 2 refractory coeliac disease have been reported to have low positive serum transglutaminase 2-antibody levels, despite a strict gluten-free diet.2-5 This might be considered as a sign of ongoing gluten ingestion and one could argue that these patients have been mis-classified as having truly nonresponsive condition. Due to the lack of reliable tools it is often challenging to uncover minor dietary lapses or inadvertent gluten intake. In Finland, there is a high prevalence of clinically diagnosed coeliac disease, and the majority (approximately 90%) of the patients adhere to a strict gluten-free diet. On a long-term gluten-free diet intestinal mucosa recovers in 96% of coeliac patients, and the prevalence of refractory coeliac disease is rare in Finland.6 In the current study,2 nonresponsive coeliac disease patients were from this well-defined patient cohort. The patients here had been followed up for a median of 10 years (up to 30 years) meaning that dietary adherence had been rigorously assessed not only once but several times over the years. In addition to 4-day food records, the patients had been interviewed repeatedly by a trained dietitian and coeliac disease experts to uncover hidden gluten traces. Based on these assessments, the strictness of the gluten-free diets of nonresponsive cases was equivalent to that of responsive cases. Finally, regardless of the impact of trace gluten ingestion, the anti-deamidated gliadin peptide assays described were able to distinguish histologically nonresponsive patients from histologically responsive patients with high accuracy. With regard to the second point, we have applied the definition of latent refractory coeliac disease as previously introduced,5 wherein symptoms are required for a diagnosis of refractory coeliac disease, and did not manifest in the latent group until sometime after blood was collected. The authors' declarations of personal and financial interests are unchanged from those in the original article.2