WAS and Wiskott-Aldrich syndrome: In addition to the T cell pathology notoriously associated with WAS, many of these functional defects also affect B cells [such as migration toward a chemokine gradient (8)] and NK cells (12, 13), and there is evidence from murine studies, that WIP has WASP-independent effects on B cell function, being a regulator of CD19 activation and PI3K/Akt signaling in B cells (14).