PSIP1 and systemic lupus erythematosus: Therefore, it was suggested that the presence of isolated anti-DFS70 antibodies could be used to help to rule out a diagnosis of AARD including systemic lupus erythematosus (SLE), systemic sclerosis (SSc), inflammatory idiopathic myopathies (IIM), Sjögren’s syndrome (SjS) and mixed connective tissue disease (MCTD) [9–12].