The co-occurrence of other autoimmune diseases within patients with systemic sclerosis (SSc) is a frequent condition affecting about one quarter of SSc-patients according to a recent meta-analysis performed by our group. Polyautoimmunity as well as the familial aggregation of autoimmune diseases strengthen the concept of “shared autoimmunity”, suggested by recent genetic studies. Epidemiologic studies have reported wide ranges of prevalence of co-occurrence of other autoimmune diseases in SSc. In our meta-analysis, based on 6102 SSc patients, the most prevalent associated autoimmune diseases were autoimmune thyroiditis (10.4%) followed by Sjogren Syndrome (7.7%) and dermatomyositis/polymyositis (5.6%), whereas co-occurrence of primary biliary cirrhosis, rheumatoid arthritis and systemic lupus erythematosus was observed in less than 5% of the patients. Some reports have suggested that patients with SSc and polyautoimmunity might have a milder disease, could occur more frequently in women and would be associated with the limited cutaneous subtype of SSc and anticentromere positive autoantibodies. However, we will present in the session cases illustrating that some SSc-patients with polyautoimmunity may develop a more severe SSc with severe organ damages. Further studies are warranted to increase the knowledge about the mechanisms of autoimmunity and polyautoimmunity and the specificities of this SSc-phenotype, in order to raise potential new approaches for the management and the treatment of SSc-patients with polyautoimmunity.
Disclosure of Interest Y. Allanore Grant/research support from: Actelion, Bristol-Meyers Squibb, Inventiva, Pfizer, Roche/Genentech, Servier., Consultant for: Actelion, Bayer, Biogen, Bristol-Meyers Squibb, Inventiva, Medac, Pfizer, Roche/Genentech, Sanofi-Aventis and Servier.