We, here, demonstrated that the percentage of circulating monocytes expressing CD16 is significantly higher in Chronic Lymphocytic Leukemia patients than in MBL patients or in normal donors and we further determined that there is a direct correlation between the percentage of “intermediate monocytes” and the entity of bone erosion, in a group of 17 CLL patients evaluated by X-ray CT scan. The gene discussed is FCGR3A; the disease is B-cell chronic lymphocytic leukemia.