Gliadin: Simple protein, one of the prolamines, derived from the gluten of wheat, rye, etc. May be separated into 4 discrete electrophoretic fractions. It is the toxic factor associated with CELIAC DISEASE.Celiac Disease: A malabsorption syndrome that is precipitated by the ingestion of foods containing GLUTEN, such as wheat, rye, and barley. It is characterized by INFLAMMATION of the SMALL INTESTINE, loss of MICROVILLI structure, failed INTESTINAL ABSORPTION, and MALNUTRITION.Glutens: Prolamins in the endosperm of SEEDS from the Triticeae tribe which includes species of WHEAT; BARLEY; and RYE.Transglutaminases: Transglutaminases catalyze cross-linking of proteins at a GLUTAMINE in one chain with LYSINE in another chain. They include keratinocyte transglutaminase (TGM1 or TGK), tissue transglutaminase (TGM2 or TGC), plasma transglutaminase involved with coagulation (FACTOR XIII and FACTOR XIIIa), hair follicle transglutaminase, and prostate transglutaminase. Although structures differ, they share an active site (YGQCW) and strict CALCIUM dependence.Triticum: A plant genus of the family POACEAE that is the source of EDIBLE GRAIN. A hybrid with rye (SECALE CEREALE) is called TRITICALE. The seed is ground into FLOUR and used to make BREAD, and is the source of WHEAT GERM AGGLUTININS.Immunoglobulin A: Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory IgA (IMMUNOGLOBULIN A, SECRETORY) is the main immunoglobulin in secretions.Prolamins: A group of seed storage proteins restricted to the POACEAE family. They are rich in GLUTAMINE and PROLINE.Flour: Ground up seed of WHEAT.Lactoglobulins: Globulins of milk obtained from the WHEY.Intestinal Mucosa: Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.Diet, Gluten-Free: A diet which is devoid of GLUTENS from WHEAT; BARLEY; RYE; and other wheat-related varieties. The diet is designed to reduce exposure to those proteins in gluten that trigger INFLAMMATION of the small intestinal mucosa in patients with CELIAC DISEASE.Pancreatin: A mammalian pancreatic extract composed of enzymes with protease, amylase and lipase activities. It is used as a digestant in pancreatic malfunction.Hemadsorption Inhibition Tests: Serological tests that measure anti-hemadsorption agents such as antiviral ANTIBODIES that block VIRAL HEMAGGLUNININS from adhering to the surface of red blood cells.HLA-DQ Antigens: A group of the D-related HLA antigens found to differ from the DR antigens in genetic locus and therefore inheritance. These antigens are polymorphic glycoproteins comprising alpha and beta chains and are found on lymphoid and other cells, often associated with certain diseases.Antigens, Plant: Substances found in PLANTS that have antigenic activity.Anaphylaxis: An acute hypersensitivity reaction due to exposure to a previously encountered ANTIGEN. The reaction may include rapidly progressing URTICARIA, respiratory distress, vascular collapse, systemic SHOCK, and death.Enterocytes: Absorptive cells in the lining of the INTESTINAL MUCOSA. They are differentiated EPITHELIAL CELLS with apical MICROVILLI facing the intestinal lumen. Enterocytes are more abundant in the SMALL INTESTINE than in the LARGE INTESTINE. Their microvilli greatly increase the luminal surface area of the cell by 14- to 40 fold.Jejunum: The middle portion of the SMALL INTESTINE, between DUODENUM and ILEUM. It represents about 2/5 of the remaining portion of the small intestine below duodenum.