CD79A and agammaglobulinemia: In contrast, the European Society for Immunodeficiencies (ESID) [10] criteria emphasize the (i) presence of low IgA, (ii) usage of low switched memory B cells, instead of measurement of antibody response to vaccine, (iii) exclusion of profound T-cell deficiency, and (iv) a clinical manifestation of disease such as an increased susceptibility to infection, autoimmune manifestations, granulomatous disease, or unexplained polyclonal lymphoproliferation, or an affected family member with antibody deficiency.