According to the European Society for Immunodeficiencies (ESID), the clinical criteria to design CVID as clinical diagnosis must include (i) at least one of following: increased susceptibility to infection, autoimmune manifestations, granulomatous disease, unexplained polyclonal lymphoproliferation or affected family member with antibody deficiency; (ii) marked decrease of IgG and marked decrease of IgA with or without low IgM levels; and (iii) at least one of the following: poor antibody response to vaccines or low switched memory B cells. Here, CD79A is linked to agammaglobulinemia.