The quest for a biomarker of circulating osteoclast precursors

Osteoclast precursors arise from the CD14+ CD16- population in controls but details about cell surface marker expression and functional characteristics of these cells is unknown, particularly in patients with inflammatory arthritis. In a recent issue of Arthritis, Research and Therapy, Lari and colleagues found that osteoclasts developed from a proliferative CD14+ CD16- subset in healthy controls. These cells took on the morphology of osteoclasts, expressed mRNA for osteoclast-related genes and excavated pits on bone wafers. These findings provide new insights into monocyte diversity and provide evidence that osteoclast precursors arise from a small proliferating monocyte population in controls. Additional studies are needed in patients with inflammatory arthritis.