Does the secretion of cytokines in the periphery reflect their role in bone metabolic diseases?

Much interest has been focused on the role of the immune system in bone remodeling. Here, we compare the production of Interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) by peripheral blood mononuclear cells (PBMC) in elderly Paget's patients, elderly osteoporotic patients and in normal elderly subjects. We studied Paget's patients (71.00 +/- 3.74 years), 7 osteoporotic patients (71.86 +/- 3.23 years), age and sex matched, and 5 elderly healthy control subjects (74.20 +/- 4.10 years) An ELISA test was used to quantify IL-1 beta and IL-6 in the supernatant culture of PBMC stimulated by phytohemagglutinin (PHA). IL-1 beta and IL-6 production from Paget's patients (IL-1 beta, 651.43 +/- 95.92 pg/ml; IL-6, 1402.85 +/- 148.11 pg/ml) was not statistically different from the production observed in the osteoporotic patients (IL-1 beta, 552.57 +/- 79.04 pg/ml; IL-6, 1458.85 +/- 118.35 pg/ml) and in the healthy elderly group (IL-1 beta, 717.60 +/- 131.34 pg/ml; IL-6, 1502.40 +/- 211.90 pg/ml). Although IL-1 and IL-6 can be involved in the bone remodeling process, we did not find any difference when we compared their production by PBMC in elderly normal, elderly osteoporotic and elderly Paget's patients.