However, the presence of circulating autoantibodies in WAS patients (Dupuis-Girod et al., 2003; Schurman and Candotti, 2003) and in Was−/− mice (Humblet-Baron et al., 2007; Nikolov et al., 2010; Becker-Herman et al., 2011; Bosticardo et al., 2011) represents the first evidence of a perturbed B cell tolerance. This evidence concerns the gene WAS and Wiskott-Aldrich syndrome.