Presence of Antitopoisomerase I Antibody Alone May Not Be Sufficient for the Diagnosis of Systemic Sclerosis

Abstract

Systemic sclerosis (SSc) is characterized by altered immune function and vascular damage, which lead to extensive fibrosis. Experts underscore the importance of using SSc-specific autoantibodies to divide the disease into subsets for prognosis, management, and research1,2. One representative feature of the immunological abnormalities in patients with SSc is the presence of antinuclear antibodies (ANA) associated with autoantibody targets. The anticentromere (ACA), antitopoisomerase I (anti–topo I), anti-RNA polymerase I/III (ARA I/III), and anti-Th/To constitute about 80–85% of autoantibodies specific for SSc and can assist the physician in assessment3,4,5. The 2013 classification criteria for SSc provide 3 points (toward a 9-point diagnosis) for patients who test positive for anti-ACA, anti-ARA III, or anti–topo I antibodies1. All 3 classical autoantibodies remain stable throughout the course of disease and tend to have a mutually exclusive association. While the presence of anti–topo I antibodies is thought to be highly specific and diagnostic for SSc, the significance of certain positive results remains unclear6,7. Since the development of ELISA to detect anti–topo I antibodies, a number of different … Address correspondence to Dr. T.M. Frech, University of Utah, Internal Medicine, 30 N. 1900 E., Salt Lake City, Utah 84132, USA. E-mail: tracy.frech{at}hsc.utah.edu