Antibodies to topoisomerase II in idiopathic pulmonary fibrosis.

Antibodies to DNA topoisomerase II (anti-topoisomerase II) were detected by ELISA in the sera of 18 out of 41 (44%) patients with idiopathic pulmonary fibrosis (IPF). Follow-up sera were also obtained from 19 of the patients. DNA topoisomerase II binding remained constantly high or low in the majority of follow-up sera, but 2 out of the 8 positive cases became negative while 3 out of the 11 negative cases became positive during follow-up. No association was found between occurrence of anti-topoisomerase II antibodies and any indices of disease severity. Furthermore, individual patient follow-up did not show any correlation between changes in topoisomerase II binding and deterioration or improvement of clinical status. In conclusion our study shows that although anti-topoisomerase II are detectable in a large fraction (approximately 50%) of IPF patients and are useful for diagnostic purposes, they do not provide a measure of clinical activity.