These studies suggest that immunodeficiencies that are characterized by impaired B cell function and reduced levels of IgA and IgM (e.g. common variable immune deficiency, CVID), and which are associated with mucosal inflammatory and autoimmune diseases (Cunningham-Rundles 2010) that might result from the loss of the antigen ‘excretion’ pathway (Strugnell and Wijburg 2010), a pathway facilitated by SAbs. This evidence concerns the gene CD40LG and common variable immunodeficiency.