[Highly sensitive apo B assay and its clinical significance]

Two sensitive and accurate methods for the determination of apo B using polyclonal antibody for human purified LDL are reported. Modified one step EIA by sandwich method is highly sensitive and serum has to be diluted by 1,000-3,000 times, but suited for the diagnosis of hypo or abetalipoproteinemia, detailed analyses of lipoprotein subfractions and in vitro study of lipoprotein metabolism. Latex method is moderately sensitive (serum dilution: 100 times), automated, simple and accurate with CV, 1.5-2.5%. Serum apo B assay is useful not only for the diagnosis of hyperlipidemia, hypolipidemia, but also for the analyses of atherogenic lipoproteins which are frequently associated with large vessel atherosclerotic changes in diabetes, obesity and coronary, cerebral or peripheral vascular diseases. A family pedigree of elevated apo B with frequent association of diabetes (type 2 b) and prominent hypercholesterolemia with autoimmune apo B antibody has been described. In obesity, either hyperinsulinemia or hyperglycemia plays a role in the elevation of VLDL and IDL probably through hepatic overproduction of VLDL. The size of VLDL tends to be larger in VLDL while IDL and LDL seem to become smaller judging from relative lipid contents to apo B.