Targeted immunotherapies in systemic sclerosis

Systemic sclerosis (SSc) is a heterogeneous systemic disorder characterised by alterations of the microvasculature, disturbances of the immune system and massive deposition of collagen and other matrix substances in connective tissue. Recent genetic studies have underlined the importance of the autoimmune component of the disease. Biologic therapies target molecules involved in the mechanisms of the immune system, such as cytokines (TNF-α, IL-6), immune cells (B cells) or co-stimulation molecules (CTLA4), and are currently used in several autoimmune rheumatic diseases, in particular rheumatoid arthritis. These drugs provide an alternative to the existing treatment methods of disease-modifying anti-rheumatic drugs and other immunosuppressive medications. Since some of the molecules targeted by biologic therapies are known to contribute to fibrosis in vitro or in animal models of experimental fibrosis, and considering that preliminary data are now available regarding the efficacy and safety of targeted immunotherapies in SSc, we aim to report with this review the results obtained in animals and humans for the biotherapies that have already been developed.