Because dural sinus macrophage depletion is associated with monocyte infiltration as early as 3 days after CLL treatment, and these monocytes can differentiate into both LYVE-1+ and LYVE-1– macrophages, these LYVE-1+ CCL21– cell clusters were possibly derived from uneven monocyte infiltration and differentiation to macrophages at day 7 after CLL treatment. Here, CCL21 is linked to B-cell chronic lymphocytic leukemia.