Monocytes from healthy donors can differentiate into NLCs.

(A) Blood mononuclear cells from a patient with CLL were cultured for 14 days to allow for outgrowth of NLCs (arrows). (B) CD14⁺mononuclear cells were isolated from the blood of a healthy donor and then cultured with sorted CD19⁺ leukemia cells of a patient with CLL. This resulted in the outgrowth of large round adherent cells (arrows) that had the same morphology as that of NLCs. (C-D) Logarithmic fluorescence histograms of cells stained with a fluorochrome-conjugated MA2.1, a mAb specific for HLA-A2 (shaded histograms), or a fluorochrome-conjugated isotype control mAb of irrelevant specificity (open histograms). Panel C depicts the fluorescence of stained NLCs that developed from the nondepleted blood mononuclear cells of an HLA-A2⁺ patient with CLL. Panel D presents the fluorescence of NLCs that developed in cultures of CD19⁺ cells of an HLA-A2⁺ CLL patient cocultured with the CD14⁺ blood mononuclear cells of a healthy donor who was negative for HLA-A2. The data shown are representative of 3 different experiments.