Iloprost modulates the immune response in systemic sclerosis.

BACKGROUND: Iloprost has been suggested to possess anti-inflammatory and immunomodulating actions and it is widely use as a vasodilatator in systemic sclerosis (SSc). In this study we evaluate the effect of iloprost on immune response in SSc patients. To this extend we enrolled 15 women affected by SSc and infused iloprost for 5 days. The effect of iloprost on T cells and monocytes was measured by flow cytometry, Real time PCR and measuring cytokines production in vivo and in vitro by ELISA. RESULTS: Our results demonstrate that Iloprost reduces T cell and TNF alpha production both in vivo and in vitro. It reduces T regulatory cells number, but increases their activity after immune stimulation. It increases serum IL-2 and this increase persists 28 days after the last infusion, also RANKL was increased both in vivo and in vitro. We observed no effect on IFN gamma production. CONCLUSIONS: These results suggest that iloprost has anti-inflammatory and immunomodulating effects, reducing TNF alpha production by T cells and the number of T regulatory cells and increasing IL-2 and RANKL.

Estrogen deficiency increases osteoclastogenesis up-regulating T cells activity: a key mechanism in osteoporosis.

Compelling evidences suggest that increased production of osteoclastogenic cytokines by activated T cells plays a relevant role in the bone loss induced by estrogen deficiency in the mouse. However, little information is available on the role of T cells in post-menopausal bone loss in humans. To investigate this issue we have assessed the production of cytokines involved in osteoclastogenesis (RANKL, TNFalpha and OPG), in vitro osteoclast (OC) formation in pre and post-menopausal women, the latter with or without osteoporosis. We evaluated also OC precursors in peripheral blood and the ability of peripheral blood mononuclear cells to produce TNFalpha in both basal and stimulated condition by flow cytometry in these subjects. Our data demonstrate that estrogen deficiency enhances the production of the pro-osteoclastogenetic cytokines TNFalpha and RANKL and increases the number of circulating OC precursors. Furthermore, we show that T cells and monocytes from women with osteoporosis exhibit a higher production of TNFalpha than those from the other two groups. Our findings suggest that estrogen deficiency stimulates OC formation both by increasing the production of TNFalpha and RANKL and increasing the number of OC precursors. Women with post-menopausal osteoporosis have a higher T cell activity than healthy post-menopausal subjects; T cells thus contribute to the bone loss induced by estrogen deficiency in humans as they do in the mouse.