Longitudinal study of anticentromere and antitopoisomerase-I isotypes

The isotypes of anti-CENP-B, the major anticentromere antibody (ACA), and antitopoisomerase I in patients with scleroderma and Raynaud's disease were studied longitudinally in order to determine whether there was evidence of isotype switch. One hundred and three sera samples from 13 ACA(+) patients and 6 antitopoisomerase I patients were studied over a period from 3 to 17 years. Anti-CENP-B was always IgG, whereas antitopo-I was IgG and IgA. IgM anti-CENP-B and IgM antitopoisomerase I, when present, were always found with IgG and/or IgA. Three patients developed IgG anti-CENP-B during the study. We conclude that anti-CENP-B and antitopoisomerase I show evidence of isotype switch with persistence of IgG expression which suggests a continued antigen-driven immune response.