Three two-site apoA-I immunoassays using phage expressed detector antibodies – Preliminary clinical evaluation with cardiac patients

Abstract High density lipoproteins (HDL) are a heterogenous group of subpopulations differing in protein/lipid composition and in their anti-atherogenic function. There is a lack of specific and robust assays which can target the functionality of HDL with respect to atherosclerosis. With recently generated CAD HDL targeted, single chain recombinant antibodies (scFvs) we set out to design and optimize apoA-I tests to compare it with conventional HDL-C and apoA-I analyses for diagnosis and risk assessment of coronary artery disease (CAD) and its outcome. Three highly sensitive two-site apoA-I assays: 022-454, 109-121 and 110-525 were optimized. A preliminary clinical evaluation of these assays, after proper sample dilution procedure, was performed using samples derived from 195 chest pain patients (myocardial infarction (MI), n = 86 and non-MI, n = 109), collected at the time of admission and at discharge from hospital (hospital stay ≤ 24 hrs). The clinical performance of the assays was compared with apoA-I measured with polyclonal anti-apoA-I antibody using conventional ELISA. ApoA-I data was in addition compared with HDL-C concentration of the samples. The concentration of apoA-I was significantly lower in MI patients than in non-MI individuals with assay 022-454 (admission and discharge samples, P