Histology of lymph node infiltrated by B-CLL cells. Ubiquitously present B-CLL cells were positive for CD23 and CD5. Scattered CD3⁺ T cells were present throughout the LN. The absence of clusters of BCL-6⁺ cells excluded the presence of germinal center remnants in the LNs. Ki67/CD20 and Ki67/CD3 double staining indicate that the majority of cycling Ki67⁺ cells (pink) were also CD20⁺ (brown) (see inset), whereas the CD3⁺ T cells were predominantly Ki67 negative. Magnification ×40.