To investigate whether the HDR-mediated integration of a correct WAS cDNA restores sufficient levels of WASp to correct T cells intrinsic defects, we delivered CRISPR/Cas9 and AAV6 reagents to CD3/CD28 activated WASp-deficient T-cells harvested from the PB of three different WAS patients. This evidence concerns the gene CD28 and Wiskott-Aldrich syndrome.