Non-celiac gluten sensitivity: an emerging syndrome with many unsettled issues

Non-celiac gluten sensitivity is still an undefined syndrome with several unsettled issues despite the increasing awareness of its existence. Gluten is likely responsible for the clinical picture in a subset of patients, whereas in other cases it concurs to this syndrome together with fermentable mono-oligo-disaccharides and polyols and wheat proteins (e.g., amylase trypsin inhibitors). Innate immunity plays a pivotal role in the development of this syndrome, which is characterized by gut inflammation without villous atrophy and likely changes of intestinal barrier function. Data on its epidemiology are still undefined and largely variable. In the USA its prevalence varies from 0.6% to 6% in primary or tertiary care, respectively. Clinically, patients complain of gastrointestinal and extra-intestinal symptoms triggered by the ingestion of gluten without evidence of celiac disease and wheat allergy. Intestinal symptoms resemble those of irritable bowel syndrome, whereas neurological signs are quite common among extra-intestinal manifestations. So far, there are no biomarkers for non-celiac gluten sensitivity, but about half of patients shows anti-gliadin antibodies of immunoglobulin G class. Although not specific for non-celiac gluten sensitivity, the detection of such antibodies can support the diagnosis in patients with gluten-related symptoms. In the absence of diagnostic biomarkers a double-blind, placebo-controlled food challenge is currently the best way for confirming non-celiac gluten sensitivity. Studies aimed at clarifying the pathophysiological, clinical and laboratory features of non-celiac gluten sensitivity will help a better management of patients with this novel and intriguing clinical entity.