Model validation using ibrutinib treatment to block CLL infiltration in NOG mice. (A) Mean number of CLL cells in the spleen of CLL-PBMC transplanted NOG mice (CLL patient #12) with control vehicle treatment (n = 5) or after 14 days of ibrutinib (25 mg/kg BW) treatment (n = 5) which was started one week post-transplantation and was administered once a day orally. (B) Mean number of CLL cells in the femur of CLL-PBMC transplanted NOG mice (CLL patient #12) after two weeks of ibrutinib treatment (25 mg/kg BW, n = 5). (C) Mean number of CLL cells in the PB of CLL-PBMC transplanted NOG mice after 14 days of ibrutinib treatment (25 mg/kg BW, CLL patient #12, n = 5). (D) NACE staining from spleen sections of CLL-PBMC transplanted control and ibrutinib treated (25 mg/kg BW, CLL patient #12, n = 5) NOG mice. Image size: x100 original magnification for images (bar indicates 200 µM). (E) IHC staining for human CD20 in the spleen of CLL-PBMC transplanted NOG mice after two weeks of ibrutinib treatment (25 mg/kg BW, CLL patient #12, n = 5. Image size: x25 original magnification for left images (bar indicates 500 µm), ×100 original magnification for images in the middle (bar indicates 200 µm) and ×400 original magnification for right images (bar indicates 50 µm)).