Multiplexed detection of agents affecting erythropoiesis (AAEs) and overall strategy for optimizing initial testing procedure

Erythropoietin receptor agonists (ERAs) are drugs acting on the early erythropoietic stages developed to treat anemia and other erythropoiesis disease and are prohibited by the World Anti-Doping Agency (WADA). As an alternative to ERAs, a new drug, belonging to the transforming growth factor-b inhibitors family, was recently developed to treat diseases linked to ineffective erythropoiesis. This drug, named as Luspatercept (Reblozyl®), is acting on the later stages of erythropoiesis to promote erythrocytes. This drug might be used by cheating athletes either independently or in combination with ERAs. Indeed, it was shown that Luspatercept and recombinant erythropoietin (rEPO) can act synergistically to increase red blood cells production, potentially allowing the use of lower doses for an efficient effect. Our aim was to find a way to combine the detection of ERAs and Luspatercept without impacting the sensitivity and specificity of ERAs detection from the current techniques implemented in antidoping laboratories and to reduce the time of analysis and total sample volume needed. Magnetic beads coated with antibodies were preferred for IP of samples for its potential multiplexing. Then, the following steps of the method were selected considering that SAR/SDS-PAGE are the electrophoretic methods authorized for initial testing procedure by WADA and that biotinylated primary antibodies used for the immunodetection results in the best sensitivity and specificity and is time saving. The method developed in this work for the combined detection of agents affecting erythropoiesis (AAEs) showed specificity, sensitivity, and robustness and is easily and quickly implementable to all antidoping laboratories.