ABSTRACT
INTRODUCTION: Dermatomyositis are rare autoimmune diseases. The discovery of specific antibodies such as the anti-TIF1γ, anti-SAE1/2 and anti-NXP2 antibodies has been associated with specific clinical phenotypes. The recent development of standardized kits based on immunodot method is a progress in dermatomyositis diagnosis. Here, we report the clinical characteristics of patients carrying these antibodies with or without clinical setting of dermatomyositis. METHODS: This single-center french retrospective study was conducted from November 2014 to February 2017 at Bordeaux university hospital. Patients carrying anti-TIF1γ, anti-SAE1/2 and anti-NXP2 antibodies, detected by immunodot, were included. RESULTS: Among the 58 patients included, only 10 were finally diagnosed with dermatomyositis. Some form of cancer was found in all anti-TIF1γ antibodies positive patients associated with dermatomyositis. Among the 48 anti-TIF1γ, anti-SAE1/2 and anti-NXP2 antibodies positive patients without clinical phenotype of dermatomyositis, 30 had autoimmune or inflammatory condition and 39 patients presented a significant biological autoimmunity. None of them developed dermatomyositis during the follow-up. CONCLUSION: The immunodot kit allowed the diagnosis of 10 dermatomyositis. A high number of autoantibody positive patients without dermatomyositis raises the issue of the immunodot's performances in the context of biological autoimmunity.
