CD79A and selective IgA deficiency disease: The European Society for the Study of Celiac Disease (ESsCD) guidelines suggest that IgA-transglutaminase type 2 (IgA-TG2) antibody is the best single test for CD detection at any age, along with total IgA levels, which should be always assessed to rule out IgA-deficiency, which occurs in up to 8% of CD patients [14].