Circulating Anti-Nuclear Antibodies in Systemic Sclerosis: Utility in Diagnosis and Disease Subsetting

The presence of circulating anti-nuclear antibodies (ANAs) is a hallmark of immune dysregulation in patients with systemic sclerosis (SSc). Currently, a variety of SSc-specific ANAs, including anticen-tromere, anti-topoisomerase I, and anti-RNA polymerase III antibodies, have been well characterized, and their commercial kits are available worldwide. Since these autoantibodies are specifically detected in SSc patients and are associated with unique sets of disease manifestations, they are widely used in routine clinical practice for diagnosis, clinical subgrouping, and prediction of future organ involvements and prognosis. In addition, SSc-specific ANAs are also useful in predicting future development of SSc in patients with Raynaud's phenomenon without any scleroderma skin changes, because their production often precedes onset of SSc symptoms. Application of circulating SSc-specific ANA measurement to clinical practice has greatly improved patient care, but utility of the autoantibody testing could be maximized by combining other clinical information, such as degree and extent of skin thickness and disease duration.