A and B: Jejunal section from a subject without celiac disease. It is a negative sample. In A, IgA deposits (in green) are detected only inside plasma cells, whereas tissue transglutaminase (in red) is evident around
the crypts and in the subepithelial area. B: Confocal analysis with a scatter plot of the image. In this plot, no area of colocalization is evident around the diagonal
of the Cartesian graphic. C and D: Jejunal section from a type 1 diabetic patient with a high serum level of anti-TG2 autoantibodies. In C, IgA deposits (in yellow-orange) are present in a patchy distribution in the subepithelial area and around mucosal vessels.
These IgA/anti-TG2 antibody colocalization areas have been analyzed by confocal microscopy. The related scatter plot is shown
in D, and the image of this area of colocalization is represented by orange dots. E and F: Jejunal section from a patient with untreated celiac disease with positive serum anti-TG2 antibodies and EMAs, in which
thick IgA anti-TG2 antibody deposits are evident just under the superficial epithelium and around the vessels (E). This subepithelial area has been studied by confocal microscopy, and the related scatter plot (F) shows an extensive area of IgA deposits/TG2 colocalization. (A high-quality digital representation of this figure is available
in the online issue.)