Celiac disease (CD) and wheat allergy are the most studied forms of gluten-related disorders characterized by an immune response (autoimmune in CD and IgE-mediated in wheat allergy). Non-celiac gluten sensitivity (NCGS) apparently is not driven by an aberrant immune response. NCGS is characterized by a heterogeneous clinical picture with intestinal and extra-intestinal symptoms arising after gluten ingestion and rapidly improving after its withdrawal from the diet. The pathogenesis of NCGS is largely unknown, but factors such as the stimulation of the innate immune system, direct cytotoxic effects of gluten, and the synergy with other wheat molecules are suspects and any one, or any combination of any and all may all play a role. Diagnostic procedures remain problematic due to the absence of efficient diagnostic markers; therefore, diagnosis is based on the symptomatic response to a gluten free diet and the recurrence of symptoms after gluten reintroduction. While the timing of gluten reintroduction in evaluating NCGS is challenging, once the determination is made, the withdrawal of gluten from the diet appears to be the correct patient management approach for those with NCGS.
Eli L, Roncoroni L, Bardella MT. Non-celiac gluten sensitivity: Time for sifting the grain. Wordl J Gastroentero. 2015 Jul 21;21(27):8221-6.