IL18 and rheumatoid arthritis: Osteoporosis is associated with low-grade inflammation both Th1 than Th2 type, since the bone turnover is regulated in a complex way: TNF-α, IL-1, IL-6, IL-11, IL-17 and glucocorticoids enhance bone resorption, while IFN-γ, IL-12, IL-18 and IL-4 inhibit bone resorption; osteoporosis is in fact associated both with diseases with a predominant Th1 cytokine pattern, such as atherosclerosis and rheumatoid arthritis, and conditions with a Th2-dominated cytokine pattern, such as ageing, menopause, pregnancy, HIV, steroid or cyclosporine therapy [157].