TGM2 and selective IgA deficiency disease: Numbers of individuals with elevated levels of IgG antibodies against tissue transglutaminase (tTG) and/or deamidated gliadin peptides (DGP), HLA-DQ2/DQ8, celiac disease (CD) and gluten free diet (GFD) among patients and blood donors with IgA deficiency (subgroups without positive serology are not shown).