Dynamic changes in CXCR4 and CD69 expression on CLL cells in different anatomic compartments. (A) CXCR4 was quantified by flow cytometry on CD19⁺-gated cells and expressed as the percentage of cells expressing CXCR4 above isotype control. Samples obtained simultaneously from the same patient are connected by a line. Mononuclear cells were obtained by density gradient centrifugation, maintained on ice, and analyzed within 24 hours. Normal B cells constituted less than 1% of CD19⁺ cells. Comparison was by paired t test. (B) CD69 was quantified by flow cytometry on CD19⁺-gated cells and expressed as the percentage of cells expressing CD69 above isotype control. Sample collection and analysis were as in panel A.