ENPP2 and mixed connective tissue disease: Furthermore, increased ENPP2 mRNA expression was detected in pDCs from patients with systemic lupus erythematosus (SLE), adult-onset Still’s disease (AOSD), mixed connective tissue disease (MCTD), and idiopathic inflammatory myopathy (IIM) than in DCs from healthy volunteers (Figure S4C), suggesting that overexpression of ENPP2 in pDCs may be a common theme in inflammation.