Disease-associated anti-bovine serum albumin antibodies in type 1 (insulin-dependent) diabetes mellitus are detected by particle concentration fluoroimmunoassay, and not by enzyme linked immunoassay.

We recently developed a particle concentration fluoroimmunoassay for the measurement of serum antibodies to bovine serum albumin in patients with Type 1 (insulin-dependent) diabetes mellitus. We observed elevated IgG-anti-bovine serum albumin antibodies in 100% of newly-diagnosed diabetic children and in 2.5% of matched control children. Here we compare the fluoroimmunoassay and the more commonly available enzyme linked immunoassay technique, exchanging coded serum samples from 40 newly-diagnosed diabetic children and 179 control children between two laboratories. Particle concentration fluoroimmunoassay detected elevated IgG-anti-bovine serum albumin antibodies in all diabetic children, enzyme immunoassay in 25% (p less than 0.0001). Fluoroimmunoassay detected elevated levels in 2.2% and enzyme immunoassay in 10% of control children (p less than 0.002). Elevated IgA-anti-bovine serum albumin antibodies in patients were slightly more often detected by fluoroimmunoassay than by enzyme immunoassay, while in control children enzyme immunoassays detected elevated levels three times more often (p less than 0.01). Values measured in either assay showed overall no correlation in either patient (IgG:rs = 0.28; IgA:rs = 0.11) or control sera (IgG:rs = 0.02; IgA:rs = -0.05). Fluoroimmunoassay for IgG was 100% disease-sensitive (enzyme immunoassay: 25%, p less than 0.0001) and more disease-specific (IgG; p less than 0.02). Our findings demonstrate that these assay techniques detected distinct subsets of anti-bovine serum albumin antibodies with little (IgG) or some (IgA) overlap. In fluoroimmunoassay procedures, antigen:antibody binding occurs within 1-2 min while hours are allowed in an enzyme immunoassay.(ABSTRACT TRUNCATED AT 250 WORDS)