Systemic bone effects of biologic therapies in rheumatoid arthritis and ankylosing spondylitis

Inflammatory joint diseases are responsible of chronic systemic inflammation, joint degradations, deformities, and altered quality of life. Patients suffering from chronic rheumatic diseases also present increased bone fragility and increased fracture risk. Registration of biologic therapies has deeply modified care in rheumatic diseases, especially in rheumatoid arthritis and ankylosing spondylitis. The available biologics are the anti proinflammatory cytokine therapies (TNF alpha blockers, anakinra and tocilizumab) and the biologics active on T cell activation (abatacept and rituximab). These drugs succeeded in blocking disease activity and joint degradation. They are also able to stop systemic bone loss among patients with inflammatory rheumatic diseases. In this review, we present the current understanding of the inflammatory-induced bone loss and the skeletal effects of biologic therapies in inflammatory joint diseases.