Comment on Immunoassays Developed for Pregnancy-Associated Plasma Protein-A (PAPP-A) in Pregnancy May Not Recognize PAPP-A in Acute Coronary Syndromes

Abstract

Qin et al. (1) recently discussed the limitations of pregnancy-associated plasma protein-A (PAPP-A) immunoassays developed for use during pregnancy to study acute coronary syndromes (ACS). That report and the authors’ related article in Clinical Chemistry (2) have important implications, because PAPP-A has been suggested to be a prognostic marker of cardiac risk (3). We have reported on the direct relationship between serum PAPP-A concentrations and both the extent and complex morphology of angiographic coronary artery stenoses in patients with chronic stable angina pectoris (4)(5). These studies were performed with the same assay that was used in the first clinical report on PAPP-A and ACS by Bayes-Genis et al., who described a relationship between PAPP-A and unstable atherosclerotic plaques (3). This assay was based on a polyclonal capture antibody and a combination of monoclonal detection antibodies. It was calibrated with WHO reference standard 78/610, which was derived from serum collected from pregnant women. The findings of Qin et al. (1)(2), raise questions concerning …