<prompt> Anti topoisomerase 1 is marker ofSystemic sclerosisClassical polyaeritis nodosaNephrotic syndromeRheumatoid ahritis  <response>: Ref Robbins 9e 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. 