Non-celiac gluten sensitivity (NCGS) is a condition characterized by gastrointestinal and extraintestinal symptoms which are triggered by gluten ingestion in the absence of celiac disease (CD) and wheat allergy. In the last years studies suggested that wheat components other than gluten can be responsible of symptom's triggering, thus the term non-celiac wheat sensitivity (NCWS) has been proposed as a more appropriate label. To date, different pathogenetic mechanisms have been proposed, but no conclusive data have been reported; among these, some study groups a possible role of innate immunity and of Natural Killer (NK) cells. KIR (Killer Immunoglobulin-like Receptors) regulate the activation of NK cells through their interaction with Human Leucocyte Antigens (HLA). Both KIR and HLA loci are highly polymorphic, and, in the case of KIR, two main haplotypes have been identified: A and B. Haplotype A is the simplest and correlates mainly with NK inhibition, while haplotype B has a variable number of genes, most of which activate NK cells. The investigators hypothesis is that the genetic variants of KIR, which define the haplotype inhibitor or activator, can affect the development and the course of NCWS too. Thus, the researchers aimed to:1. Identify putative KIR genetic variants in NCWS patients (50 subjects) respect to celiac disease patients (50 subjects) and blood donors (50 subjects); 2. Evaluate the possible association of KIR genetic variants with specific clinical manifestations of patients with NCWS.