These subpopulations respond rapidly during the acute inflammatory phase, particularly during bacterial infection.[36] A clear association between focal bone erosion in RA and overactivation of localized osteoclasts has been demonstrated according to available studies.[37] Osteoclasts, as a type of multinucleated cells, are mainly derived from monocyte/macrophage lineage, especially CD14+CD16− monocytes.[38] Studies have indicated that CD16+ monocytes have a high rate of spontaneous apoptosis and a more significant expression of apoptosis-related genes. This evidence concerns the gene CD14 and rheumatoid arthritis.