WAS and Wiskott-Aldrich syndrome: In support of a role for the actin cytoskeleton, peripheral blood mononuclear cells (PBMCs) from Wiskott-Aldrich syndrome (WAS) patients, where mutations in the WAS protein (WASP) results in defective Cdc42-induced regulation of the actin cytoskeleton [80], are resistant to CD47-induced apoptosis [77].