Number of Circulating CD14-Positive Cells and the Serum Levels of TNF-α Are Raised in Acute Charcot Foot

C harcot neuro-osteoarthropathy (CNO) is a devastating complication of diabetes characterized by increased local bone resorption mediated by osteoclasts. Often CNO leads to multiple fractures and joint destruction resulting in severe deformity of the foot. Osteoclasts are multinucleated cells that have a common precursor with monocytes/ macrophages (1). Previously, we reported that the number of osteoclasts generated in vitro from circulating cells was higher in acute CNO patients compared with diabetic control subjects and was partially independent from receptor activator for NF-kB (RANK)-RANK ligand (RANKL), the main osteoclastogenic mediator (2). One hypothesis could be that the number of circulating osteoclast precursors is increased in CNO. Among all monocytes subpopulations, CD14-positive cells are the most potent to transform into bone-resorbing osteoclasts (3). We studied 11 diabetic patients with recent onset of acute CNO, 10 diabetic patients with no previous history of CNO, and 6 healthy control participants. All patients were matched for age, sex, and duration of diabetes. Mean serum creati-nine and vibration perception threshold on the apex of the hallux were not different between CNO and diabetic patients. Patients with bone diseases (oste-oporosis, rheumatoid arthritis, Paget's disease) were excluded from this study. This study had research ethics committee approval and was carried out in accordance with the Declaration of Helsinki. Peripheral blood mononuclear cells were isolated and the number of CD14-positive monocytes was determined by flow cy-tometry. Serum concentration of tumor necrosis factor (TNF)-a, interleukin-1b, and LIGHT were determined by ELISA. Data were compared using Mann-Whitney U test and linear regression analysis.