25 Jul
Scl 70 (topoisomerase 1) is a nucleolar enzyme. Scl 70 antibodies are considered to be specific for scleroderma (systemic sclerosis) and are found in up to 60% of these patients. Scl 70 antibodies are more common in patients with extensive skin involvement and interstitial pulmonary fibrosis, and are considered a poor prognostic sign.