Anti-DFS70 Antibodies: A Useful Biomarker in a Pediatric Case With Suspected Autoimmune Disease abstract

Antidense fine speckles 70 (anti-DFS70) antibodies, a peculiar antinuclear antibody (ANA) pattern by indirect immunofluorescence, is frequently observed in ANA-positive individuals with no evidence of systemic autoimmune rheumatic disease. They may be found in many different inflammatory conditions and in healthy individuals. We herein report a case of an 8-year-old girl presenting with generalized edema, hypertension, hepatomegaly, and a history of pharyngitis, which occurred 3 weeks earlier. Laboratory analysis revealed low complement C3 (6 mg/dL), microhematuria, and proteinuria. A diagnosis of acute glomerulonephritis was made. Anti-dsDNA, antiextractable nuclear antigens, and antineutrophil cytoplasmic antibodies were negative. However, a highly positive (1:640) ANA immunofluorescence test with dense fine speckles pattern was found. The presence of anti-DFS70 immunoglobulin G antibodies was confirmed by a specific immunoassay. In conclusion, the presence of isolated anti-DFS70 antibodies may be useful to exclude an autoimmune pathogenesis in those children with a positive ANA test and a clinical picture possibly attributable to systemic autoimmune rheumatic disease. This will avoid further unnecessary investigation with the potential for incorrect diagnosis and possibly harmful treatment. Pediatrics 2014;134:e1–e3 AUTHORS: Martina Fabris, MD,ab Silvia Zago, MD,b Raffaello Tosolini, MD,c Paola Melli, MD,c Nicola Bizzaro, MD,d and Elio Tonutti, MDe aInstitute of Clinical Pathology, cPediatric Clinic, and eLaboratory of Immunopathology and Allergy, University Hospital S. Maria Misericordia, Udine, Italy; bInstitute of Clinical Pathology, DSMB, University of Udine, Udine, Italy; and dLaboratory of Clinical Pathology, San Antonio Hospital, Tolmezzo, Italy