Various serum lipid levels (hypo-, normo- and hyper-cholesterolemic) are shown in dys-β-lipoproteinemia (-LP). Though type III hyper-LP (hypercholesterolemic dys-β-LP) is characterized by abnormal lipid composition of VLDL and elevaied level of apolipoprotein E (apo E), diagnosis of normo- and hypo-cholesterolemic dys-β-LP are offenly difficult. At the present study, we established simple and sensitive methods to diagnose dys-β-LP only by measurement of serum apolipoproteins. In purpose to define new approach for diagnosis of dys-β-LP, serum apo B, apo C-II, apo C-III and apo E levels were determined by the method of single radial immunodiffusion. These apolipoproteins were analysed in subjects with dys-β-LP (n=7), hyper-LP (n=67) and normo-LP (n=41). A serum apo E/apo C-III ratio in dys-β-LP was 1.37±0.59 (mean±SD). This value was significantly higher than the ratios among normo-LP (0.45±0.17), type IIa (0.51±0.11), type IIb (0.45±0.17), type IV (0.45±0.13) and type V (0.47±0.22). A serum apo E/apo B (×100) ratio in dys-β-LP was 25.2±10.2. This value was also significantly higher than the ratios among normo-LP (4.4±1.5), type IIa (4.0±0.9), type IIb (4.7±1.9), type IV (7.2±3.1) and type V (15.5±5.9). Based on these data, it is proposed that the apo E/apo C-III ratio of >1.0 was diagnostic value of type III and the apo E/apo B (×100) ratio of >10.0 was also diagnostic value of normo- and hypo-cholesterolemic dys-β-LP. As to determine serum apolipoproteins very simple by single radial immunodiffusion method, the ratios will be useful for diagnosis and detection of dys-β-LP in clinical and epidemiological studies.
