Phenotypic and histologic analyses of CLL cells in the IRF4^−/−Vh11 mice. (A) Splenocytes from IRF4^+/+ Vh11 and IRF4^−/−Vh11 mice were stained with antibodies against CD19, B220, IgMa, IgMb, CD21, CD23, IgD, and CD1d. The stained cells were analyzed by FACS. The data were presented as a histogram under a B-cell gate. Dark line, IRF4^−/− Vh11 CLL cells; light line, IRF4^+/+ Vh11 B cells. (B) Spleens and livers were isolated from 5-month-old IRF4^−/−Vh11 and IRF4^+/+Vh11 mice. The tissues were fixed, sectioned, stained with H&E. The spleen sections are shown at ×2.5 and ×40; the liver sections are shown at ×20. Arrow indicates the infiltrated CLL cells in liver.