TransFix® for delayed flow cytometry of endothelial progenitor cells and angiogenic T cells

Endothelial progenitor cells (EPC) and angiogenic T cells have not been validated for use in studies that involve delayed sample processing and analysis. Here, we report our results for the flow cytometric enumeration of circulating EPC and angiogenic T cells using TransFix®-treated whole blood obtained from adult patients with cardiovascular disease and healthy volunteers. Both cell types promote neovascularization and vascular homeostasis. As such they have been put forward as novel diagnostic markers for endothelial dysfunction and may add prognostic information in patients with cardiovascular disease. Our findings indicate that by the addition of TransFix® cellular antigen stabilizing reagent to whole blood, analyses can be postponed up to 7 days after blood collection. Therefore, this procedure may facilitate laboratory workflow, as well as the organization of multicenter studies, which requires analyses to be conducted in a central core laboratory.