Mechanisms involved in the pathogenesis of bone derangement in celiac disease. GFD: gluten-free diet; IFN: interferon-gamma; IL: interleukin; IGF-1: insulin growth factor-1; GH: growth hormone; OPG: osteoprotegerin; RANK/RANKL: receptor activator of nuclear factor kappa B/receptor activator of nuclear factor kappa B-ligand.