Anti topoisomerase 1 is marker of

Ref Robbins 9/e p228 B cell activation also occurs, as indicated by the pres- ence of hypergammaglobulinemia and ANAs. Although there is no evidence that humoral immunity plays a signifi- cant role in the pathogenesis of SS, two of the ANAs are viually unique to this disease and are therefore useful in diagnosis (Table 4-10). One of these, directed against DNA topoisomerase I (anti-Scl 70), is highly specific; it is present in as many as 70% of patients with diffuse scleroderma (and in less than 1% of patients with other connective tissue diseases) and is a marker for the devel- opment of more aggressive disease with pulmonary fibro- sis and peripheral vascular changes. The other ANA is an anticentromere antibody, found in as many as 90% of patients with limited scleroderma (i.e., the CREST syn- drome); it indicates a relatively benign course.