CLL B cells from CLO-responding samples devoid of NLCs (thereby responding to CLO only in the CD40L + IL-4 activation setting, not in the CpG + IL-15 setting) were seeded on the bottom of a well and stimulated with CpG + IL-15 to elicit cell-cycle entry, required for CLO-responsiveness. This evidence concerns the gene IL15 and B-cell chronic lymphocytic leukemia.