CD79A and agammaglobulinemia: For all patients analyzed, the capacity to produce IgA and IgG in vitro was significantly impaired compared with healthy controls (Fig. 1 B), which is in line with the hypo- or agammaglobulinemia and reduced numbers of switched memory B cells observed in these patients (Fig. 1 A; de Greef et al., 2011; Weemaes et al., 2013).