Blockade of ITK via Ibrutinib may also affect adhesion properties of donor T cells as evidenced by increased β1 integrin surface expression upon Ibrutinib treatment (C in S5 Fig) A similar phenomenon has already been shown in the clinic, where several patients with CLL being treated with Ibrutinib showed decreased platelet aggregation due to ineffective platelet adhesion mediated by integrins [41]. Here, ITK is linked to B-cell chronic lymphocytic leukemia.