Immune changes in post-menopausal osteoporosis: the Immunos study

Abstract

Our results suggest that, regardless of age and estrogen status, postmenopausal OP is associated with immune changes, highlighting a possible role of IFN-gamma in the pathophysiology of OP and reporting, for the first time, changes in several B lymphocyte populations. These alterations may reflect the frailty observed after fracture, providing new insight into the mechanisms of morbidity and mortality associated with OP fractures.

Osteoimmunology: from mice to humans

“…Nevertheless, changes in several B lymphocyte populations in patients affected by postmenopausal osteoporosis regardless of their estrogen status have been shown. 51 The role of B cells in the control of bone turnover has been studied in other diseases that affect bone, such as RA 48,52 and periodontal inflammation. 53 These studies suggest that B cells may be involved in the control of bone turnover in humans as well, mainly by the production of cytokines such as OPG and RANKL.…”

Innate Immune Responses in the Geriatric Population

“…It affects one out of three women after menopause (Breuil et al, 2010). Oestrogen deficiency leads to an uncoupling between activity of bone resorbing cells (osteoclasts) and bone forming cells (osteoblasts) responsible for accelerated bone loss.…”

“…The concept of osteoimmunology recently emerged from increasing evidence of intimate links between bone tissue and the immune system. Indeed, recent studies have suggested that the increase in bone resorption induced by oestrogen deficiency is at least partly mediated by increased paracrine production of bone resorbing cytokines (Breuil et al, 2010). Multiple soluble mediators of immune cell function, including cytokines, chemokines and growth factors also regulate osteoblast and osteoclast activity.…”

“…Multiple soluble mediators of immune cell function, including cytokines, chemokines and growth factors also regulate osteoblast and osteoclast activity. This is particularly true in pathological conditions such as rheumatoid arthritis and inflammatory bowel disease (Breuil et al, 2010). IL-1 is one of the most potent stimulators of bone resorption and IL-6 appears to be a potent osteotrophic factor that may play an important role in diseases characterized by increased bone resorption.…”

“…In contrast, Il-1, IL-6, TNF are significantly higher in whole blood after polyclonal activation in osteoporotic women than controls and negative correlation is found between lumbar bone mineral density and IL-1, IL-6 or TNF levels (De Martinis et al, 2005;Zheng et al, 1997). A study performed on osteoporotic women and controls without oestrogen or vitamin D deficiencies shows that osteoporotic women present a decrease in circulating B cells, decreased basal secretion of IFN by CD4+ T lymphocytes, a decreased in memory CD4+ T cells expressing RANK+ and CD28+ (Breuil et al, 2010). The TNF-family RANK-L and its receptor RANK are key regulator and essential for the development and activation of osteoclasts.…”