The introduction of cereals in human nutrition 10 000 years ago caused the 
occurrence of gluten induced diseases. This protein complex is involved in 
pathogenesis of wheat allergy, celiac disease, and gluten sensitivity. Wheat 
allergy and celiac disease are mediated by the system of adaptive immunity. 
Gluten sensitivity is a recently defined entity induced by innate immune 
mechanisms. These subjects present various intestinal and particularly 
extraintestinal symptoms. The differences between celiac disease and gluten 
intolerance include permeability of the intestinal mucosal barrier, histology of 
duodenal biopsy, and mucosal gene expression. The symptoms of gluten sensitivity 
may also have another genetic background of food intolerance independent of the 
HLADQ2, - DQ8 system and tissue transglutaminase (eg. in some psychiatric 
disorders). At present, there is no specific bio-marker of gluten sensitivity. 
The diagnosis is possible only by exclusion of other causes of symptoms and 
improvement on a glutenfree diet applied in a doubleblind placebo controlled 
manner with optional sequence of both stages to exclude the placebo effect due 
to nutritional intervention.