Celiacdisease isan intestinalmalabsorptioncharacterizedby an intolerance to cereal proteins accompanied by immuno-logical responses to dietary gliadins and an autoantigen located in the endomysium. The latter has been identified as the enzyme tissue transglutaminase which belongs to a family of enzymes that catalyze protein cross-linking reac-tions and is constitutivelyexpressed inmany tissues aswell as being activated during apoptosis.