Influence of Phosphatidylethanolamine Concentration and Composition on the Detection of Antiphosphatidylethanolamine Antibodies by ELISA

Background Accumulating evidence supports a positive correlation between the presence of antiphosphatidylethanolamine (aPE) autoantibodies and clinical symptoms of antiphospholipid syndrome (APS). However, there is a lack of standardized ELISA‐based method for detecting aPE. The current study was conducted to investigate the dependence of aPE ELISA on lipid concentration and composition of PE antigens. Methods A range of ELISA conditions were examined by varying the concentrations of egg PE and by substituting egg PE with combinations of synthetic DOPE and DSPE. The physical properties of the synthetic PE species were also characterized. Results Our data indicated that there are different optimal PE concentrations for conducting ELISA assays for cofactor‐dependent and cofactor‐independent aPEs. In addition, using a two‐component synthetic lipid system, we demonstrated aPE ELISA readouts can be modulated to approach the performance level of egg PE, which is currently the most commonly used PE antigen. Conclusion These data raised the possibility of ultimately replacing natural PE antigens with a blend of defined synthetic lipid species, thus overcoming a known variable factor in aPE detection. The outcome of this study will help pave the way to developing a standardized aPE test.