Development of a radioimmunoassay for human deoxyribonuclease I

Abstract

A reliable radioimmunoassay (RIA) for human deoxyribonuclease I (DNase I) is described. Using delayed addition of tracer antigen, the method is sensitive (9.5 ng/ml), reproducible and specific. A good parallel relationship was observed between the standard curve and dilution curves for human urine and human pancreatic juice. G-actin, a naturally occurring DNase I inhibitor, caused no change in the immunoreactivity of DNase I. In healthy individuals, aged 11–90 yr, the mean serum DNase I was 18.4 ng/ml (sd 6.7 ng/ml). Increased serum DNase I occurred in patients with acute pancreatitis, renal failure, and in about one-third of patients with various malignant tumors.