Antibodies to Scl-70 (DNA topoisomerase I) are detected in nearly 75% patients with Progressive Systemic Sclerosis (PSS). Patients of Scleroderma with Scl-70 antibody positivity are associated with diffuse cutaneous involvement, increased frequency of pulmonary fibrosis and high mortality. Centromere antibodies are most often associated with lower frequency of pulmonary fibrosis and mortality although an increased risk for pulmonary hypertension has been observed.